Old Southern Butter Cookies

Original recipe found here

Old Southern Butter Cookie
2 c flour
3/4 c sugar
1/2 tsp baking powder
1 tsp salt
3/4 cup softened butter
2 tbsp (heaping) fresh chocolate mint, chiffonaded and minced
1 large egg
1/2 tsp vanilla
*Important Note: it will take quite a bit of mint, perhaps more than one cup of fresh mint leaves, to produce 2 very large tablespoons of finely chiffonaded (cut into very fine strips) and mince (chop strips into tiny specks) mint.
Preheat oven to 375 degrees. Sift together flour, baking powder, and salt. Set aside. In another bowl combine butter with sugar, and mix until smooth. Add egg and mix well. Add vanilla and mint to mixture. Add sifted flour mixture to butter mixture. Roll dough into a log approximately two inches in diameter and chill for several hours before slicing into 1/4 inch slices. Bake for 12 minutes.