Line cookie sheet with foil.

Microwave semisweet chocolate in bowl on medium power 1 minute; stir. Keep microwaving at 15-second intervals, stirring, until melted and smooth; set aside. Repeat process with white chocolate.

Spread semisweet chocolate on prepared cookie sheet about 1/3-inch thick. Drop tablespoons white chocolate on top. Swirl chocolates together with tip of knife to marble. Sprinkle with crushed candy.

Refrigerate 1 hour, or until firm. Peel off foil; break bark into pieces. It will keep for about a month in an airtight container in refrigerator.