1 ¼ cup old fashioned oats
1 ½ cup all-purpose flour
1 teaspoon baking powder
1 teaspoon baking soda
¼ teaspoon salt
1 cup unsalted butter, softened
1 cup firmly-packed soft brown sugar
½ cup granulated sugar
1 large egg
¼ cup Irish Cream liqueur
1 teaspoon pure vanilla
¼ cup mint-flavored chocolate chips
Place oats in a food processor and run until the oats are ground up like flour. Whisk together the oat flour, flour, baking powder, baking soda and salt. Beat the butter and sugars in a bowl until light and fluffy. Beat in the egg, liqueur, and vanilla. Gradually beat in the flour at a low speed. Fold in the chocolate chips. Put the mixture into the fridge for 15 minutes to chill and firm up.
Preheat the oven to 350°. Drop by rounded teaspoon, about 21/2 inches apart (these cookies will spread while cooking) onto an ungreased baking sheet. Bake on the middle rack of the oven for 8-10 minutes or until the edges start to brown. Remove from oven and allow to cool on the baking sheet for 2-3 minutes then transfer to a wire rack to cool completely. Store in an airtight container.