In the bowl of a stand mixer fitted with a paddle attachment, cream butter until light and fluffy. Add salt and vanilla each. Begin adding powdered sugar ¼ cup at a time. Once sugar is in, add heavy cream as needed to reach desired consistency.

Divide the buttercream into 3 bowls and add a tiny bit of gel food color to each bowl. Stir until the color is completely blended in.

To decorate the cupcakes, I used a basketweave tip, a flower tip, and a star tip. I filled a decorating bag with each color and just alternated tips. They’re monsters so you can’t really mess them up! Top with eyeballs.