Tie-Dye Cupcakes

In a medium bowl, whisk together oil and sugar until combined. Whisk in 1 egg until smooth. Wash and dry whisk. Add the red, blue, and yellow food coloring to three separate small bowls; stir a few drops of water into each bowl until dissolved.

In a second medium bowl, whisk together flour, baking powder, and salt. Slowly add flour mixture and ⅔ cup milk to the oil mixture, alternating dry ingredients and milk; stir until just combined. Divide batter evenly between bowls of food coloring; stir until coloring is evenly distributed.

Arrange the cupcake cups on the baking sheet. Gently layer colored batters into each cupcake cup, filling each just over half full, to create a tie-dye pattern. Bake until a toothpick inserted into the center of a cupcake comes out clean, 18-22 minutes. Let cool to room temperature.

Meanwhile, in a third medium bowl, beat softened butter with a hand mixer until pale, then slowly add confectioners’ sugar. Beat for 2-3 minutes. Stir in 1 tablespoon milk or water until smooth and creamy.