Yellow Birthday Layer Cake with Chocolate Frosting
- Cake
- 2 ½ cups all-purpose flour, spooned and leveled (315 g)
- 2 ½ tsp baking powder
- ½ tsp baking soda
- 1 tsp kosher salt
- 1 cup unsalted butter, softened (227 g), plus more for the pans
- 1 ½ cups granulated sugar, 300 g
- 4 large eggs, room temperature
- 1 tbsp vanilla extract
- 1 cup buttermilk, room temperature (240 ml)
- Chocolate frosting
- 1 cup unsalted butter, softened (227 g)
- 3 cups powdered sugar, 360 g
- ¾ cup unsweetened cocoa powder, 64 g
- ¼ tsp kosher salt
- 2 tsp vanilla extract
- ¼–⅜ cups heavy cream, or milk
- sprinkles, for decorating (optional)
Yellow Birthday Layer Cake with Chocolate Frosting
- Heat the oven to 350°F (175°C). Butter two 9-inch round cake pans, line the bottoms with parchment circles, then butter the parchment and dust the pans with flour.
- In a medium bowl, whisk the flour, baking powder, baking soda and salt.
- In a stand mixer with the paddle, beat the butter and sugar on medium-high until very pale and fluffy, scraping the bowl once.
- Add the eggs one at a time, beating about 30 seconds after each. Beat in the vanilla.
- With the mixer on low, add one-third of the flour mixture, then half the buttermilk. Repeat, ending with the last of the flour. Mix only until each addition disappears.
- Divide the batter evenly between the pans (weigh them for matching layers) and smooth the tops.
- Bake until golden, the tops spring back when pressed and a toothpick in the center comes out clean.
- Cool the cakes in their pans on a rack.
Yellow Birthday Layer Cake with Chocolate Frosting
- Run a thin knife around the edges, turn the cakes out onto the rack and peel off the parchment. Let them cool completely.
- For the frosting, beat the butter on medium until creamy. Sift in the powdered sugar and cocoa and mix on low until combined.
- Add the salt, vanilla and 4 tablespoons of cream. Beat on medium-high until fluffy, adding more cream a spoonful at a time if it is too stiff to spread.
- If the cake tops are domed, slice them level with a long serrated knife.
- Set one layer on a plate. Spread about 1 cup of frosting over it right to the edge.
- Place the second layer on top, cut side down. Spread a thin layer of frosting over the top and sides to trap crumbs.
- Chill the cake so the crumb coat firms up.
- Spread the rest of the frosting over the top and sides with an offset spatula, then add sprinkles if you like.