3/4 cup butter
3 cups all-purpose flour
1/3 cup unsweetened cocoa powder
2-1/4 cups sugar
1-1/2 tsp. vanilla
.75 oz Blue Food Coloring (or for red: 1 1-oz. bottle red food coloring -approx 2 Tbsp )
1-1/2 cups buttermilk
1-1/2 tsp. baking soda
1-1/2 tsp. vinegar
1.Let eggs and butter stand 30 minutes. Preheat oven to 350 degrees F. Line 28 2-1/2-inch cupcake pans with paper liners; set aside.
2.In medium bowl combine flour, cocoa powder, and 3/4 tsp. salt; set aside. In large mixing bowl beat butter on medium-high 30 seconds. Add sugar and vanilla; beat until combined. One at a time, add eggs; beat on medium after each. Beat in food coloring on low.
3.Alternately add flour mixture and buttermilk to egg mixture; beat on low to medium sped after each just until combined. Stir together baking soda and vinegar. Add to batter; beat just until combined.
4.Spoon batter into prepared pans, filling each about two-thirds full. Bake 15 to 17 minutes. Cool in pan on wire rack for 5 minutes. Remove from pans. Cool completely. Top with small chocolate cookies, if desired. Dust with powdered sugar.