In a large bowl, combine the flour, baking powder, sugar, and salt. Add the butter and mix until the mixture resembles coarse crumbs. Pour the dry ingredients into the wet ingredients and stir until just combined. Fold in the chocolate chips. Spoon the batter into an ungreased 8-inch round cake pan. Bake the cake for 35 to 40 minutes or until toothpick inserted in center comes out clean. Allow to cool before cutting into squares.