I feel like almost any American can recall a time in their lives when they go to a birthday party and are presented with plain vanilla cupcakes with rainbow sprinkles, either baked into the cake, or speckled on top of a vanilla or chocolate frosting. It is honestly such a basic thing, cake, frosting, sprinkles, but at the same time, it is something that most people have grown up eating at one point or another. Personally, I have a weird experience with those generic grocery store-looking cupcakes. They are dry, crumbly, and kind of fell apart when you bit into them. And since I grew up in a neighborhood where gourmet bakeries weren’t really a thing, I came to expect that as the norm for cakes. It was not until I learned how to bake myself that I realized how duped my childhood was, and how much I wished I could have experienced a properly baked funfetti cupcake. So that was what spurred this recipe. Nostalgia, and a need to improve a past memory, just to make it up to young Fred who assumed that all cakes were supposed to taste like styrofoam.

Hot milk cake is such a fun batter to make. I first learned about it from Miette, a bakery in San Francisco. This was back in 2018(crazy that 2018 is already 6 years ago), but when I first heard that term, and realized I had 0 clue what a hot milk cake was, my inquisitive nature led to me researching about hot milk cake, what makes it unique from your average cake batter, and how I can make it at home. Hot milk cake, as the name implies, is made by heating up milk, then mixing that with whipped eggs and sugar, and then folding into that the flour to form your cake batter. Hot milk cake is different from an American cake batter in that the crumb is tender and soft, while still being moist. The heat from the milk gels the starch of the flour, and denatures the gluten, which results in a cake with a light mouthfeel from that lower gluten development, but the gelled starch allows the baked cake to retain more moisture. I wanted to use this specific batter because it is honestly a better(moister) version of that classic store-bought vanilla cupcake.

For the buttercream, I did not want to use American buttercream. The concept of whipping butter and a ton of powdered sugar together is kind of gross, the more I think about. It is literally whipped fat with way too much sugar to the point where it makes your teeth hurt. And I just personally struggle with the concept of making American buttercream for that reason. So for that reason, I went with an ermine buttercream. Ermine buttercream is a flour-based buttercream, made first by whipping milk, flour, and sugar together over the stove until a thick roux forms. Then that roux is mixed with butter to form a lighter, airier buttercream. If I am not making a meringue-based buttercream(which is my usual go-to), I would defer to either cream cheese frosting or ermine buttercream, since all of those options call for way less sugar than the standard powdered sugar-based American buttercream. The cooked milk and flour method for making ermine buttercream almost mirrors the heated milk in the hot milk cake batter, so it is, in my opinion, the perfect topping(besides whipped cream) to pair with that kind of cake.

Makes 24 cupcakes:
For the hot milk cake:
1/2 cup heavy cream
1 stick unsalted butter
1 cup milk
4 eggs
1 1/2 cups granulated sugar
a pinch of salt
1 tsp vanilla extract
1 teaspoon vanilla extract
2 1/4 cups all-purpose flour
2 1/4 teaspoons baking powder
1 cup rainbow sprinkles

In a pot on medium-high heat, melt down butter into heavy cream and milk. Once the butter is fully melted, lower the heat completely so that the milk is still warm, but not boiling. In a bowl, whip the eggs with sugar, salt, and vanilla until thick and glossy. In another bowl, sift the flour and baking powder, and mix into that the rainbow sprinkles. Combine ingredients together to form your batter. Fill 12 cupcake liners 2/3 the way full using the batter, and bake at 350 degrees F in a lined baking tray for 20 minutes. Cool completely before removing the cupcakes.

For the ermine buttercream:
1/2 cup granulated sugar
1/4 cup all-purpose flour
a pinch of salt
1/2 cup milk
1 stick unsalted butter
1 tsp vanilla extract

In a pot, whisk the sugar, flour, salt, and milk together on medium heat for 3-5 minutes, or until it begins to form a thick paste. Transfer the paste into a stand mixer and whip it with a paddle attachment for about 10 minutes, or until it is no longer warm to the touch. At this point, add in the butter and vanilla, and whisk it using a whisk attachment until everything is incorporated together. Transfer the buttercream to a piping bag with a star tip.

For garnish:
Rainbow sprinkles

Pipe the buttercream on top of the cakes and garnish the top of the cakes with the sprinkles.