Ingredients

• 2.25 cup all-purpose flour
• 2.5 teaspoon baking powder
• 0.5 teaspoon salt
• 8 ounce unsalted butter, softened
• 1.5 cup granulated sugar
• 3 eggs, room temperature
• 1 cup whole milk, room temperature
• 2 teaspoon vanilla extract
• 12 ounce unsalted butter
• 1 cup unsweetened cocoa powder
• 0.67 cup water, hot
• 3.5 cup powdered sugar
• 0.5 teaspoon salt
• 1 teaspoon vanilla extract

Steps

1. Preheat oven to 350°F. Grease and flour two 9-inch round cake pans, or line the bottoms with parchment paper for easier removal.
2. In a medium bowl, whisk together flour, baking powder, and salt. Set aside.
3. In a large mixing bowl, cream together the softened butter and granulated sugar using an electric mixer on medium speed until light and fluffy, approximately 3 minutes.
4. Add eggs one at a time to the butter mixture, beating well after each addition and scraping down the bowl as needed.
5. Stir in the vanilla extract until combined.
6. Alternately add the flour mixture and milk to the butter mixture, beginning and ending with flour. Mix on low speed just until combined after each addition, stirring gently with a rubber spatula.
7. Divide batter evenly between the prepared pans and smooth the tops with an offset spatula.
8. Place pans in the preheated oven and bake for 30-32 minutes, or until a toothpick inserted in the center comes out clean or with just a few moist crumbs.
9. Remove pans from the oven and let cool for 10 minutes at room temperature.
10. Turn cakes out onto wire cooling racks and allow to cool completely, approximately 1 hour, before frosting.
11. While cakes cool, prepare the chocolate frosting. In a large mixing bowl, whisk together the cocoa powder and hot water until smooth and well combined.
12. Add the softened butter to the cocoa mixture and beat on medium speed with an electric mixer until creamy.
13. Gradually add powdered sugar, salt, and vanilla extract, beating on low speed until combined, then increase speed to medium and beat for 2 minutes until smooth and spreadable. If frosting is too thick, add 1 tablespoon milk at a time; if too thin, add more powdered sugar 1 tablespoon at a time.
14. Once cake layers are completely cool, place the first layer on a cake turntable or serving plate. Spread a thick layer of chocolate frosting on top using an offset spatula, leaving a 1/2-inch border.
15. Carefully place the second cake layer on top, aligning it evenly with the first layer.
16. Frost the top and sides of the entire cake with the remaining chocolate frosting, using smooth, even strokes with the offset spatula for a polished finish.
17. Slice and serve the cake at room temperature. Store covered at room temperature for up to 2 days, or refrigerate for up to 5 days.