In mixing bowl, combine sugar, butter, egg, milk (water), and vanilla. Beat an medium speed on electric mixer until light and fluffy (no sugar clumps) Add flour, baking powder and salt. Beat at low speed until soft dough forms. Divide in half.

In mixing bowl (shove the dough aside and just reuse) combine half of dough and the melted mint chocolate chips. Beat at low speed until well blended

On lightly floured wax paper, roll chocolate dough into 1/8 inch thick rectangle. On second sheet roll remaining dough into 1/8 inch thick rectangle

(Here's the tricky bit) Turn the white dough rectangle carefully onto chocolate rectangle matching edges as best you can. Discard the top layer of wax paper

Roll the dough jelly roll style (peel off the wax paper as you roll) and pinch the edges to seal when you're done rolling. Wrap in plastic wrap or just reuse your wax paper.

Stick it in the fridge for 2 - 3 hours until firm.

Heat your oven to 350F Cut the roll into 1/4 inch slices. Place slices 2 inches apart on ungreased cookie sheets. Bake for 8 to 10 minutes or until sit.