This is perhaps the simplest bark to make. It's almost as easy as picking up a package of bark at the store, but why not make it yourself if you can? It's white chocolate, semisweet chocolate, and some shortening, all melted and swirled together. You really can't go wrong.
Swirled Bark (from Nestlé, 1991)
One 8-oz. pkg. (4 foil-wrapped bars)
Nestlé semi-sweet chocolate baking bars
3 tablespoons vegetable shortening, divided
One 6-oz. pkg. (3 foil-wrapped bars) Nestlé Premier White baking bars
Melt semi-sweet chocolate baking bars and 1 tablespoon shortening, stirring until smooth. Remove from heat; set aside. Melt over hot (not boiling) water, Premier White baking bars and remaining 2 tablespoons shortening, stirring until smooth. Remove from heat.
Drop spoonfuls of melted semi-sweet baking bars and melted Premier White baking bars alternately into 13x9-inch pan. Swirl mixtures with tip of knife to marbleize. Refrigerate until firm, about 1½ hours. Break into pieces to serve. Store in refrigerator.
Note: I've used Ghirardelli white chocolate chips instead of Nestlé and chocolate chips instead of baking bars. All work well.