HEAT oven to 350°F. Lightly grease 2 (9-inch) round baking pans. Beat first 6 ingredients in large bowl with mixer on low speed just until moistened, stopping frequently to scrape bottom and side of bowl. Beat on medium speed 2 min. Stir in chopped chocolate and 2 Tbsp. crushed candy. Pour into prepared pans.
BAKE 50 min. to 1 hour or until toothpick inserted in centres comes out clean. Cool in pans on wire racks 10 min. Loosen cakes from sides of pans with spatula or knife. Invert cakes onto racks; gently remove pans. Cool cakes completely.
FILL and frost cake with Cool Whip. Sprinkle with remaining crushed candy. Keep refrigerated.
serving size = 1 piece (86 g)