Cream the butter on medium speed until light and fluffy, about 2 to 3 minutes.

Slowly add the sweetened condensed milk while mixing on low speed, then add peppermint extract and mix until smooth.

Gradually sift in powdered sugar and mix until the dough is soft and lump-free, about 4 to 5 minutes.

Divide the dough for food coloring if desired, and mix thoroughly to achieve the desired shades.

Shape small portions of the dough into balls, about 1 inch in diameter, or use cookie cutters for fun shapes.

Let the mints set at room temperature for about 1 hour, or refrigerate for 15 to 20 minutes for firmer mints.