Make ahead; Gift idea
Combine first 6 ingredients, stirring well. Add butter, and stir or beat at low speed with an electric mixer until mixture is crumbly. Reserve 1 1/2 cups crumb mixture; press remaining crumb mixture into a lightly greased 13" x 9" pan. Bake at 375° for 10 minutes. Cool on a wire rack. Reduce oven temperature to 350°.
Place 1 cup chocolate pieces in a microwave-safe bowl; microwave at HIGH 1 to 1 1/2 minutes, stirring after 30 seconds. Press chocolate pieces with the back of a spoon to mash them. (The candies will almost be melted with pieces of color coating still visible.) Stir in condensed milk. Spread mixture evenly over crust in pan, leaving a 1/2" border on all sides.
Combine reserved 1 1/2 cups crumb mixture and remaining 1/2 cup chocolate pieces; sprinkle evenly over chocolate mixture, and press lightly.
Bake at 350° for 25 to 28 minutes or until golden; cool in pan on wire rack. Cut into bars.