Preheat the oven to 350 F. In a large bowl, mix together butter and sugar until smooth. Add in the mint extract. Add in the flour, and mix until it is fully combined.
Add in the food coloring and mix until it is fully green. Fold in the chocolate chips. Roll the cookie dough into balls, and flatten slightly. Place the cookies onto a large ungreased baking sheet at least 2-inches apart. Bake for 10-12 minutes.