Hidden surprise heart cake!

Have I got your attention yet? :P I hope you all had a nice Valentine’s Day weekend! It also happened to be Chinese New Year on the same day as Vday, which is pretty rare. My mom called me and informed me that the next time Chinese New Year falls exactly on Vday will be in another 38 years, at which point I thought about how hugely different life will be 38 years later… Anyway, I visited my boyfriend in California this past week to celebrate Vday with him and to take a little breather after finishing a rough block of med school classes just now. We had a lovely time extending Valentine’s Day into a 3-day weekend of fun, which included lots of yummy food, of course! Since no Vday is ever complete without some baking, yours truly of course had plans to spoil her beloved. Turns out, he surprised me first, with a Baker’s Edge brownie edge pan for a present! He knows how much I absolutely adore brownie edge pieces, so I am a very happy girl indeed :)

Well, not to be outdone, I had my own ambitious project up my sleeve. Just the week before, I saw the most awesome heart cake tutorial on I Am Baker, and just knew that I had to try something that epic. It’s a cake with a hidden red heart on the inside! All the way through the cake! I was just so smitten with the idea of this cake, and my Valentine’s Day visit to see my boyfriend was going to be the perfect time to try it. My gears turned and I started planning to make a much smaller version of the cake since it was just going to be the two of us eating it. I decided that a 4″ diameter cake would be just the right size for two, and secretly purchased a 4″ diameter tall souffle ramekin to bake the cake layers (I think it was a 10 oz. ramekin). I wanted this to be a complete surprise, so I divided the task into two separate days. The first day I baked the cake layers while he was at work and then froze them overnight. I made the frosting and assembled everything the next afternoon while I kept him out of the kitchen. And finally after about 6 hours of total time baking and tinkering, it was done!!! And I rushed to bring him out so I could show him. Boy was he in for a surprise ;) At first… it just looked like a small and unsuspecting cake… which he really enjoyed the decoration of. It was my very first time decorating a cake with buttercream, and also my first time with a 4-layer cake. Daunting! I didn’t do a very good job with it, but I still had a lot of fun!

I eagerly encouraged him to cut into the cake so that he could see what surprise was in store for him inside. Not only did I want to show him, I really wanted to see for myself! This is one of those cakes where you spent all this time putting it together but have no idea how it’s going to look at the end until it’s cut open, so I was definitely pretty anxious. I was keeping my fingers crossed that it would at least look presentable, and I figured I could blame it on being my first attempt if it really bombed :P And so he cut out a first slice and saw the curious looking red center on his slice, but was not sure what it was supposed to be…

And then he cut out another slice for me and peeked into the center of the cake, and there it was! A pretty red heart going all the way through the center of the cake! I was so happy to see that it came out so nicely, and he was totally floored, though he had no idea how I did it. Whew, huge breath of relief! In hindsight, although I was worried when I made the cake, it was not actually that difficult to put together. I think the frosting was the part I had the most trouble with actually, and that’s only because I’ve never frosted with buttercream before and my recipe was a bit more runny than ideal for frosting because I didn’t want to make it too sweet. The cake itself was really very delicious, just the right amount of sweet to cure a sweet tooth and the aroma of vanilla was so lovely, it actually tasted kind of like a sugar cookie in cake form, sooo good. I used Magnolia Bakery’s famous recipe for their vanilla birthday cake/cupcakes and vanilla buttercream frosting, halving both recipes so that it was just the right amount for my 4″ cake. I did not have the ingredients on hand for the red velvet cake that the original cake tutorial called for, so I just set aside some of my vanilla cake batter and dyed it red to bake separately as a few cupcakes, which worked out perfectly as a shortcut. I made some alterations to the recipe itself which is specified below in my recipe. I really hope you’ll give this gem of a cake a try! It was so much fun for me and I felt really very accomplished when it came together in the end. And really, what a nice Valentine’s Day treat :)

Hidden Surprise Heart Cake (4″ cake – serves 2-4) Recipe adapted from Recipezaar.com
Assembly tutorial adapted from I Am Baker


1/2 cup unsalted butter, softened
1 cup sugar (I eyeballed for slightly under 1 cup because I didn’t want my cake too sweet)
2 eggs, at room temp
1 1/3 cups all-purpose flour (recipe calls for mix of AP and self-rising flour, but I did a substitution)
1 tsp baking powder (just a tiny smidge under 1 tsp is ideal)
pinch of salt
1/2 cup milk
1/2 tsp vanilla
approx 1/2 tsp red gel food coloring, adjust as needed

Buttercream Frosting:
1/2 cup unsalted butter, softened
3 cups confectioner’s sugar, adjust as needed
1/4 cup milk
1 tsp vanilla


Baking the cake:

1. Preheat oven to 350 degrees F. Grease and lightly flour two 4″ souffle ramekins (10 oz. size). Cut out a circle of wax paper to line the bottoms of the ramekins for easy removal later. Also, line 3 cupcake tins with paper liners. I know, this already sounds complicated, don’t get discouraged!

2. In a mixing bowl, cream butter until smooth with an electric mixer on medium. Then gradually add in sugar and beat until fluffy, about 3 minutes.

3. Add eggs one at a time, beating well after each addition.

4. In a separate bowl, sift together flour, baking powder, and salt. Add the flour mixture to the egg mixture in 3 separate additions, alternating with the milk and vanilla. Beat until blended after each addition, but do not overbeat.

5. Separate out 1/3 of the batter and set aside. Using the remaining 2/3 of the batter, fill the two ramekins 2/3 – 3/4 of the way to the top, and begin baking in the oven. They will need at least 35 minutes to bake, start checking after 35 minutes using a toothpick inserted in the middle, they are done when the toothpicks come out clean (tops will probably be somewhat domed and cracked, but that’s fine).

6. Meanwhile, add the red gel food coloring to the 1/3 of the cake batter that you set aside. Add a little bit at a time and whisk the color in evenly until you get a nice bright pink/red color that you are satisfied with. If you choose to use liquid food coloring, I don’t know the exact proportions, but I believe 1/2 tsp of gel is equivalent to about 1 oz. of liquid, although it will interfere with the liquid proportions of the batter, so use at your own discretion.

7. Fill the 3 lined cupcake tins with the red batter (about 3/4 full) and bake in the same oven at 350 degrees F for about 20-22 minutes, until the tops spring back lightly when touched.

8. When cakes/cupcakes are done, remove from oven and let cool for 10 minutes in the pans before removing to cool on a rack.

9. When cakes are cool enough to handle, take a knife and trim off the domed/cracked tops of the cakes to flatten them (enjoy the incredibly delicious tops that you just cut off, it’s really very heavenly to munch on these scraps!). Then, split each cake horizontally in half to get 2 layers per cake. Allow layers to cool completely, then wrap each layer in saran wrap and put in the freezer overnight. For the cupcakes, peel off the paper liners and trim off the harder domed tops (but do not throw them away). Using your hands or a fork, break the cupcakes into crumbs. Seal the crumbs and the tops you cut off together in tupperware and leave on the counter overnight. The tops will soften and you’ll be able to break them into crumbs as well the next day.

Whew! Take a break! Enjoy your evening and come back for the fun stuff on day 2! :)

Making the Buttercream Frosting:
1. In a mixing bowl, place the softened butter and 2 cups of the confectioner’s sugar. Add the milk and vanilla, and beat until smooth and creamy.

2. Gradually add more confectioner’s sugar as needed to achieve a desired spreading consistency. I probably used about 3 cups of sugar total.

3. This frosting can be left at room temperature for up to 3 days, but do not refrigerate it before you use it or else it will set (although I found it sometimes useful to set it in the fridge for a little bit to firm it up before frosting, though that may be because my frosting was a little on the runny side due to my hesitation to add more sugar. The original recipe calls for up to 4 cups of sugar!)

Assembling the Cake:
now’s the interesting part, with more pictures too!

1. Take out your frozen cake layers and give them a trim to get them as flat as possible. I also stacked them on top of each other and trimmed around the edges to make sure they were more or less all the same size up and down.

2. Next, separate the 4 layers into 2 groups of 2 layers. Spread a layer of the white frosting between each of the 2 layers, to form two separate 2-layered cakes. The cold from the frozen cake should set the frosting very quickly and they will hold together well.

3. Now’s the trickiest part of the assembly. Take the first 2-layered cake, and make sure you have a way to identify it from the other one (I peeled off the outer browned cake layer from one of them so I could tell the difference). Make a little measuring tool using 2 toothpicks and a piece of string tied between them so that you can trace a circle around the inside of the cake (see I Am Baker’s example here). Now trace a circle on the surface of your cake, depending on how big you want your heart inside to be. This will be the widest part of your heart. After you trace the circle, use a knife and a slanted cutting motion, carve an upside-down cone shape out of your cake (this will be the bottom half of your heart), like thus:

4. Next, you’ll want to carve the top of the heart into the other 2-layer cake. To do so, again trace a circle with the toothpicks, trying to get as similar of a location as possible with the other 2 layers you just did. Taking your knife, now carve a small cylinder into the very center of the cake, but do not cut it out. Just carve a circle downwards into the cake. Next, using a similar slanted cutting motion, cut around the outer ring that you marked with your toothpick, trying to stop just at the cylinder that you carved in the center. Your goal is to make a channel around the cylinder.

5. After you’ve got the channel carved out, you can go back with a smaller knife and trim the center cylinder that is still standing so that it looks like a right-side up small cone. Make it as pointy as you can, as this will be the top dip of your heart shape, so a sharp point looks best. Then, using a small spoon, round out your channel around this central cone (imagine the rounded shape of the top half of a heart). This part takes some spatial imagination and I can’t tell you specifically how to do it perfectly, but I can show you my finished carving of the top half of the heart:

6. Whew! Flip the cakes over and dust out the crumbs for the best-looking appearance later. We’re not far from the finish line!

7. Now, add a few spoonfuls of your frosting to the red cake crumbs until they are nice and dense. If you’ve ever made cake balls before, the texture will be like that. I eyeballed about 1/2 cup of frosting for the red cake crumbs probably.

8. Now using a small spoon, carefully spoon your red cake into the carved out portions of your two cake halves. Press down gently to get it packed in, and only till each half so that it is level. Don’t forget to identify which half is which! When you assemble your cake together you don’t want an upside down heart… I did not use up all of my cake crumbs, which is okay. You can eat the rest :)

9. The original tutorial has you spreading a rim of frosting around the edge of the heart before putting together the two halves, but I omitted that because I was worried I might get it into the middle of the heart and look like my heart was being cut in half. I think it came out better without the center frosting in this layer, but perhaps the cake is more in danger of toppling over… haha. I didn’t have that problem though, it’s a small cake! Now just put the 2 cake halves together! Easy peasy! You can see my cake layers aren’t perfectly even and are missing a few bits here and there, but that’s okay, you won’t be able to tell later :)

10. Now all that’s left to do is to frost the cake! I added some blue gel food coloring to my frosting to get a light blue, since my boyfriend’s favorite color is blue. I set aside a few spoonfuls of the white frosting for piping on top later, and put that in the fridge to set a little. Then I applied a light coating of the blue frosting to the entire cake to seal off any crumbs (this is the crumb coat). I set the cake into the freezer for a few minutes just to let that set.

11. And then I just put on the rest of the frosting, playing around with it as I went since it was my first time working with buttercream. I put my cake back into the freezer multiple times just for a few minutes so that my frosting could set better and it was easier to layer on more frosting. While that was going on I also piped some melted chocolate onto wax paper in various shapes and put those in the freezer too for decorations. I cut up a fresh strawberry to fan out on the top of the cake as well (if you do this, do let the cut strawberry sit on a paper towel for a few minutes to make sure it does not leak juice onto the frosting). Finally, I crushed up some of my cake scraps into yellow crumbs and used that as sprinkled decorations around the bottom rim of the cake and a little on top! The chocolate decorations came out a little goofy because they melted when I touched them to adjust them. But here is the final product!!

This cake was so much fun to make and eat! I hope you enjoyed reading about the process, and get inspired to make something similar yourself :)

One response to “Hidden surprise heart cake!

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