Heat oven to 350°F. Lightly grease 9 inch square baking pan. Mix flour, baking powder and salt together. Beat butter, sugars, cocoa, eggs and vanilla together till fluffy and smooth. Stir in flour mixture till blended. Set aside 1/4 cup of each kind of chips and 2 tablespoons cherries. Fold remaining chips and cherries into dough. Spoon into prepared pan. Bake 20-25 minutes till firm in center. While still hot, cut into 16 squares. Melt reserved milk chocolate chips and drizzle over bars. Coarsely chop remaining cherries and sprinkle over top. Melt remaining white chocolate chips with shortening and drizzle over bars. Cool in pan on rack.