1Heat oven to 350°F. Spray bottom only of 13x9-inch pan with cooking spray. In large bowl, stir cookie mix, butter and egg until soft dough forms (dough will be crumbly). Using fingers, press dough in bottom of pan. Bake 15 minutes.
2Drizzle condensed milk evenly over baked crust. Sprinkle with white chips, chocolate chips, coconut and walnuts.
3Bake 30 to 35 minutes or until light golden brown. Cool completely, about 2 hours. For bars, cut into 6 rows by 6 rows.