Preheat oven to 375 degrees. Generously grease an 8×8 pan.
Sift together the flour, ginger, baking powder, and salt. Set aside.
Cream together the butter and sugar for about 5 minutes. Mixture should be light in color. Gradually add the dry mixture to the creamed mixture. Add just enough milk to help bring the dough together (one smooth, cohesive ball). Press dough into pan. Bake for 20-25 minutes.
For glaze, using a microwave or double boiler, melt together the chocolate chips and butter. Pour onto still warm ginger cookie base. Let sit for about 30 minutes or until chocolate layer is firm.