1. Heat oven to 375°F. Unwrap and coarsely chop chocolate bars; set aside.
2. Beat butter, brown sugar and granulated sugar in large bowl until well blended. Add egg, milk and vanilla; beat well. Stir together flour, baking soda and salt; gradually beat into butter mixture. With wooden spoon work chocolate bar pieces, coconut and walnuts into mixture. (Dough will be stiff.) Press mixture in ungreased 13x9x2-inch baking pan.
3. Bake 20 to 22 minutes or until edges are golden brown. (Do not over bake.) Cool completely in pan on wire rack. Drizzle VANILLA DRIZZLE over surface; allow to set. Cut into bars. Makes about 24 bars.
VANILLA DRIZZLE: Combine 1/2 cup powdered sugar and 2 teaspoons milk in small bowl. Add additional milk, 1/2 teaspoon at a time, until of desired consistency.