Preheat oven to 350F and line a muffin pan with cupcake liners.
Whisk together flour, baking powder, and salt in a bowl.
In a separate bowl, blend together egg, oil, sugar, and milk.
Blend the wet mixture into the dry ingredients.
Divide the batter into the muffin pan and bake for 20-25 minutes.
Meanwhile, blend together butter, milk, and powdered sugar in a mixing bowl.
Divide the frosting into 3 bowls. Tint one bowl with red food coloring and another with blue.
Take muffins out of the oven and leave to cool.
Alternately spoon 3 colors of frosting into a piping bag fitted with a star tip.
Pipe frosting onto cooled cupcakes and top with sugar cone tips.