Over low heat, melt butter and add brown sugar, mix well. Add chocolate chips and stir until melted. Pour into large mixing bowl, with mixer on high beat well. Let stand 10 minutes until cool.
Add eggs in one at a time and beat on high. Reduce speed to low and add dry ingredients until blended. Chill dough for one hour.
Preheat oven to 350°. Roll 1 teaspoon of dough int balls and place two inches apart on greased cookie sheet. Bake for 9 to 11 minutes.
Remove cookies from oven and place 1 mint on top of each cookie. Return to oven for one minute only, to soften chocolate mint. Remove from oven and swirl mint over cookie with a knife. Let cool completely.