Funfetti Birthday Cake

I first wrote about Momofuku's Pastry Chef, Christina Tosi, about three years ago (read it here). I've read the Momofuku Milk Bar cookbook cover to cover and I love her process and reasoning behind each product and recipe in the book. This recipe is a slight adaption of her "Birthday Cake" - the most delicious funfetti cake ever. 

There are a couple of things in this recipe that are not mainstream ingredients (IE glucose, citric acid, and clear vanilla bean extract). I found the glucose and citric acid quite easily at Surfas Culinary District here in Los Angeles but had no luck with the clear vanilla extract and no time to buy it online. I used regular brown extract and it was a fine substitute.  

If you are wondering, why she uses these ingredients, here's a quick breakdown:

Citric Acid: it provides tartness without imparting any flavor or added liquid

Glucose: reduces chance of sugar crystallization and bonds ingredients 

As far as equipment goes you will need a 6-inch cake ring, 2 strips of acetate (found easily at sur la table or williams-sonoma or surfas), and a quarter sheet pan. 

NOTE: if you want to enjoy the shortcut version of this recipe, make some cupcakes! I want to give you this option now as this recipe and process is not for the faint of heart or those short on time. 

One other note, I omitted the birthday cake crumb topping that Tosi suggests using in her book and instead topped my cake with leftover cake crumbs and edible rainbow glitter. 

Funfetti Birthday Cake

Makes 1 6-inch cake, 6-8 servings

[adapted from the Momofuku Milk Bar cookbook]

Cake Ingredients

4 Tbsp Butter, room temperature

1/3 cup vegetable shortening

1 1/4 cups granulated sugar

3 Tbsp light brown sugar, tightly packed

3 large eggs

1/2 cup buttermilk

1/3 cup grapeseed oil (or canola)

2 tsp vanilla extract

2 cups cake flour 

1 1/2 tsp baking powder

3/4 tsp kosher salt 

1/4 cup + 2 Tbsp rainbow sprinkles

Cake Method

1. Heat oven to 350 F

2. Combine butter, sugars, and shortening in bowl of a stand mixer fitted with paddle attachment. Cream together for 2-3 minutes at medium-high speed. Scrape down bowl and add eggs. Mix for another 2-3 minutes. Scrape down again. 

3. On low speed, stream in buttermilk, oil, and vanilla. Increase speed to medium and mix for 4-6 minutes until the mixture is white and twice the size of the original fluffy butter and sugar mixture. Don't rush this process. There should be no fatty streaks or broken liquid - it needs to be one homogeneous batter.  Once there, stop and scrape bowl again. 

4. On lowest speed, add cake flour, baking powder, salt, and 1/4 cup of rainbow sprinkles. Mix just until your batter comes together. Scrape bowl. 

5. Spray sheet tray with pam and line with parchment. Spread batter evenly into pan. Sprinkle remaining rainbow sprinkles over batter. Bake for 30-35 minutes or until it is golden brown and an inserted toothpick comes out clean. 

[note: this is not a quarter sheet tray - it is a half, as I doubled the recipe]

6. Let cool completely.  Make your frosting while you are waiting. You can cheat by cooling in the freezer or fridge if you want. No judgement here :)

Birthday Frosting Ingredients

8 Tbsp (1 stick) butter, at room temperature

1/4 cup vegetable shortening

2 oz cream cheese

1 Tbsp glucose  

1 Tbsp corn syrup

1 Tbsp vanilla extract

2 cups confectioner's sugar 

1/2 tsp kosher salt 

pinch baking powder

pinch citric acid

Birthday Frosting Method

1. Combine butter, shortening, and cream cheese in the bowl of your stand mixer. Using paddle attachment, mix for 2-3 minutes until smooth and fluffy. Scrape down bowl. 

2. On lowest speed, add glucose, corn syrup, and vanilla. Beat for 2-3 minutes on medium-high speed until silky smooth and glossy. 

3. Add sugar, salt, baking powder, and citric acid and mix on low speed to incorporate. Move speed to medium-high and mix for another 2-3 minutes. Boom. you're done. 

Building your Cake:

You need one more component: Birthday Cake Soak. This is 1/2 cup of whole milk and 1 tsp of vanilla extract in a small bowl that you will brush on each cake layer for added moisture as you are building (think tres leches cake but not quite as wet!). 

OK. To build the cake you need to first put a piece of parchment on the counter and invert your cake onto it. Use your cake ring to cut 2 circles from the cake (these are your top 2 cake layers) and keep the remaining cake "scrap" to use for the bottom layer of your cake. 

Clean your cake ring and position it on a clean sheet of parchment paper on a flat plate. Use 1 strip of acetate to line the inside of the cake ring. Put your cake scraps down into the ring as your bottom layer. Lightly pack it together into an even layer (as even as possible). Brush with 1/3 of your milk soak. Spread with 1/3 of your frosting. 

With your index finger, gently tuck the 2nd strip of acetate between the cake ring and the top 1/4 inch of the first strip of acetate so that you have a clear ring of acetate that is 5-6 inches tall. Set one of the cake rounds on top of your first frosting layer. Brush with another 1/3 of the milk soak and another 1/3 of the frosting. 

Repeat with the final layer of the cake. Then wrap with plastic wrap and freeze for at least 12 hours (or up to 2 weeks) and then pull it out at least 3 hours before you need to serve it. While it is frozen, peel off the acetate and remove cake ring. 

Slice into wedges and serve. Enjoy!