- Preheat oven to 350°F. Grease two 8 or 9 inch cake pans and line with parchment. 
- Whisk together flour, cocoa powder, baking powder, baking soda and salt. Set aside. - 2 cups all-purpose flour, ⅔ cup unsweetened cocoa powder, 1½ tsp baking powder, 1 tsp baking soda, ½ tsp  salt 
- With electric mixer, cream butter and sugar 3-5 minutes until light and fluffy. Beat in eggs one at a time. - 3 large eggs 
- Stir in vanilla.Whisk 1/2 cup milk into cocoa powder until smooth paste forms. - 1 cup full-fat milk (warmed), 1½ tsp vanilla extract 
- Add flour mixture and milk paste alternately in batches to butter mixture, beginning and ending with flour.  
- Fold gently after each addition just until combined.Divide batter evenly between prepared pans. 
- Bake 30-35 minutes until toothpick inserted in center comes clean. 
- Cool in pans 10 minutes before inverting onto wire racks. Cool completely before frosting. 
- Enjoy this rich, chocolatey sponge cake on its own or top it with chocolate ganache, buttercream, or your favorite frosting!