- Place butter in the bowl of an electric mixer fitted with the whisk attachment. Whip, on medium-high speed, for approximately 8 minutes, scraping the sides of the bowl every few minutes, until the butter is fluffy and has doubled in size.
- Reduce the mixer speed to medium. Add the sweetened condensed milk in 1/3 increments, waiting until the sweetened condensed milk has been whipped into the butter before adding the next batch. Continue to whip until the frosting is light and fluffy.
- Divide the frosting between 3 bowls.
- Add a few drops of food coloring to each bowl, stirring in between drops until you get the desired color.
- Once the color has been achieved, wrap each bowl with plastic, and refrigerate for 30 minutes.
- Once the frosting has cooled, prep a large piping bag with the desired tip. Carefully spoon the frosting into the bag, focusing each color to one â€œsideâ€ of the bag. Or, alternatively, you can use a special, multi-color piping kit.
- Decorate leftover cupcakes, pound cake or angel food slices with the tie dye frosting and enjoy.