Heat oven to 375 degrees F. Line 20 muffin cups with paper liners. Sift together flour, baking powder and salt onto waxed paper.
Beat sugar, butter, eggs and 1/4 cup milk in bowl at medium speed until light and fluffy, 3 minutes. Alternately, in 3 additions, beat in flour mixture and remaining milk. Spoon scant 1/4 cup of batter into each liner.
Bake in 375 degree oven 20 minutes or until golden brown and wooden pick tests clean. Remove to racks to cool.
Beat together butter, orange rind, juice, salt and sugar in bowl until smooth and creamy. Tint with food coloring if desired. Use to frost cupcakes.