1. Preheat oven to 325 degrees F. Lightly grease a 13x9x2-inch baking pan; set aside. In a medium bowl, combine flour, malted milk powder, and salt; set aside.
2. In a medium saucepan, combine butter and chocolate; heat and stir over low heat until chocolate melts. Remove from heat; stir in sugar. Using a wooden spoon, beat in eggs, one at a time. Add vanilla. Stir in flour mixture, walnuts, and half of the crushed malted milk balls. Spread in prepared pan.
3. Bake in preheated oven for 35 minutes. Cool in pan on a wire rack. Cut into bars. To package, place remaining crushed malted milk balls in a small plastic bag and include the instructions, "use a small amount of canned frosting to 'glue' malted milk ball pieces atop bars".
To Store: Layer unfrosted bars between waxed paper in an airtight container; cover. Store in refrigerator for up to 3 days or freeze for up to 3 months. Makes 30 bars.