Preheat oven to 350°F. Line standard muffin pan with baking cups. In medium bowl, combine flour, cocoa, baking powder and salt; set aside. In large bowl, cream butter and sugar with electric mixer until light and fluffy. Add eggs, icing color and vanilla extract; mix well until icing color is well incorporated (scraping down sides of bowl when necessary). Alternately add flour mixture and buttermilk to butter mixture; add water and mix well. In small bowl, combine white vinegar and baking soda; gently stir into cupcake mixture. Spoon into baking cups. Bake 20-22 minutes or until toothpick inserted comes out clean. Cool cupcakes in pan on cooling rack for 5-8 minutes. Remove cupcakes from pan; cool completely.