Mix dry ingredients in a bowl.
Mix butter, sugar, and brown sugar in another, larger bowl and blend them until they're creamed. I use a hand-mixer, my trusty SunBeam that's lasted over two decades now. I also have a firm plastic spatula that I use to occasionally press it all back together.
Blend in the eggs, and then blend in the vanilla.
Fold the dry ingredients into the wet bowl, about a third at a time, and blend them together, I use the mixer for this as well.
Knead in the mint and chocolate chips by hand, or with a spatula. Roll dough into balls, and either bake them or freeze them for baking later.
Preheat the oven to 350°F. Place them onto an ungreased cookie sheet, leaving room for them to expand. Press them down with the palm of your hand to make rounds, and then bake them until they're done, about 12 minutes. Using a spatula, put them onto plates to cool.
I've taken to making half batches of cookies, or perhaps you could call them one egg cookies. Much more reasonable amount.