Heat oven to 350° F. Line muffin cups - 2 1/2-inches in diameter) with paper bake cups.
Combine dry ingredients in large bowl. Add buttermilk, eggs, water, oil and vanilla; beat on medium speed of mixer 2 minutes (batter will be thin). Fill cups 2/3 full with batter.
Bake 15 minutes or until wooden pick inserted in center comes out clean. Remove cupcakes from pan. Cool completely. Frost with Perfectly Chocolate Chocolate Frosting.
Melt butter. Stir in cocoa. Alternately add powdered sugar and milk, beating to spreading consistency. Add small amount additional milk, if needed. Stir in vanilla. About 2 cups frosting.Servings: 2 dozen cupcakes