Happiest Birthday Cake to You!

Brown Butter Sour Cream Cupcakes with Chocolate Buttercream Frosting
For all my sweetie's sweetness, he does not have the biggest sweet-tooth. For his birthday, however, exceptions are made in the name of celebrations and cake. His birthday cake of choice? Yellow cake with chocolate frosting. I came up with this very rich, moist cake recipe playing off that classic "box cake" combo. As it so happened, our generally unlucky softball team had a game that night, so I made these "birthday cupcakes" to share. Perhaps cake and birthdays are great morale boosters . . . we won the game and got to celebrate two great things in one day with beer, pizza, and more cupcakes!

Ingredients
BROWN BUTTER SOUR CREAM CAKE
- 3 sticks butter
- 2 1/4 c. flour
- 2 1/2 tsp. baking powder
- 1 tsp. salt
- 1 2/3 c. sugar
- 1 Tbsp. vanilla paste
- 4 egg yolks
- 2 eggs
- 1 1/4 c. sour cream
- 1/4 c. whole milk

CHOCOLATE BUTTERCREAM FROSTING
- 1 c. sugar
- 3 large egg whites
- 1/4 tsp. salt
- 1 tsp. pure vanilla extract or vanilla paste
- 2 sticks plus 2 Tbsp. unsalted butter, at room temperature, cut into tablespoons
- 4 oz. extra-bittersweet chocolate, melted and cooled

BROWN BUTTER SOUR CREAM CAKE
Preheat oven to 325˚F. Lightly spritz 24 cupcake liners with cooking spray and line a standard-sized muffin tin. Set aside.

In a small, heavy-bottomed sauce pan, melt 3 sticks of butter over medium-low heat. Stir occasionally for about five minutes. The butter will get foamy. Continue to cook and stir about four minutes longer until little brown bits begin to appear and it smells fragrantly nutty. Remove from heat and allow to cool slightly before using. While the butter cools, whisk together flour, salt, and baking powder in a medium bowl and set aside.

Combine brown butter and sugar in the bowl of a stand sized mixer using the paddle attachment. Beat butter and sugar together on high speed until it is creamy and well incorporated. Add vanilla and stir to combine. Turn mixer to slow speed and add egg yolks and eggs, one at a time, alternating with portions of flour mixture until everything is well combined and smooth. Scrape down the sides of the mixer occasionally. Add sour cream and milk and beat until just combined.

Using a tablespoon, fill each cupcake liner about 2/3 full with batter. Bake cupcakes in batches for about 12 minutes until cooked through and a toothpick inserted in the center comes out clean. Turn cupcakes out on a wire rack and allow to cool completely before frosting

CHOCOLATE BUTTERCREAM FROSTING
Whisk together eggs whites and sugar in a medium-sized double-boiler. Place the double-boiler over medium-high heat and whisk together over heat until the sugar is dissolved, about 5 minutes.

Transfer the warmed egg and sugar mixture to the bowl of a stand mixer with a whisk attachment. Add vanilla and whisk together at medium-high heat until the mixture is glossy and stiff, about 8 minutes. Scrape down the sides of the bowl and turn mixer back on to medium heat. Add butter, a couple pieces at a time making sure the mixture becomes fully incorporated before adding more. Once all the butter is incorporated and mixture is light and fluffy, add melted chocolate and mix until fully blended. 

Frost cooled cupcakes with an offset spatula. Buttercreams can be delicate, store frosted cupcakes in the refrigerator if making ahead of time. Allow to sit at room temperature for about 20 minutes before serving.

 Happy birthday to you!