Everyone's Favorite Birthday Cake


Sour cream cake with chocolate cream cheese frosting


Ingredients

For the sour cream cake
2½ cups plus 2 Tbsp. (330 g.) cake flour
1 scant Tbsp. baking powder
1½ tsp. kosher salt
½ tsp. ground cinnamon
7 oz. (1¾ sticks/200 g.) unsalted butter, softened, cut into ½-inch pieces, plus more for the pans
1 cup (200 g.) granulated sugar
¾ cup (165 g.) firmly packed light brown sugar
4 large eggs
1½ (345 g.) cups sour cream


For the chocolate cream cheese frosting
4 oz. (1 stick/115 g.) unsalted butter, softened
1 (8 oz. /226 g.) package cream cheese, softened
3 to 3½ cups (340 to 395 g.) confectioners’ sugar, sifted
¼ tsp. kosher salt
3 oz. (85 g.) dark chocolate, melted and cooled



Preparation

For the sour cream cake
• Preheat the oven to 350 degrees. Butter 2 8-inch round cake pans, line them with parchment paper and butter the parchment. Dust with flour and knock out the excess.

• In a large bowl, sift together the flour, baking powder, salt and cinnamon; set aside.

• In the bowl of a standing mixer fitted with the paddle attachment, beat the butter and both sugars on medium speed until light and fluffy, about 2 minutes. Add the eggs 1 at a time and beat until just incorporated, scraping down the sides of the bowl as necessary. Reduce the speed to low; add the flour mixture in three additions, beginning and ending with the flour mixture, alternating with the sour cream, and scraping down the sides of the bowl as necessary.

• Pour the batter into the prepared pans and bake, rotating the pans halfway through, until a toothpick inserted into the center comes out clean, 35 to 40 minutes. Set the pans on a wire rack to cool for at least 20 minutes before loosening the sides of the cakes from the pans with a small knife and inverting them onto a wire rack. Remove the parchment paper and turn the cakes right side up; let them cool completely.

For the chocolate cream cheese frosting
• Beat the butter in the bowl of a standing mixer fitted with the paddle attachment until smooth. Add the cream cheese and beat until well combined. Add only 3 cups (340 g.) confectioner’s sugar and the salt; beat until smooth. Add the chocolate and mix until well combined. If the frosting seems too loose, add additional confectioners’ sugar, 1 tablespoon at a time, until it becomes thicker. Do not overheat. The frosting can be made up to 24 hours in advance and stored in an airtight container in the refrigerator; let it soften at room temperature before using.

Assembly
• Place 1 cooled cake layer on a serving platter. If necessary, trim the top to create a flat surface. Spread about ¾ cup (200 g.) of frosting on top. Add the top layer and trim if you want (some people prefer a domed cake top). Spread a very thin layer of frosting over the sides and top of the cake (called a crumb coat, this helps to keep loose cake crumbs under control when you frost the outside of the cake), and place it in the refrigerator for 10 minutes to firm up. Spread the sides and top of the cake with the remaining frosting. Refrigerate for another 10 minutes to set before serving.