Line 13 x 9-inch baking dish with aluminum foil extending 2 inches over opposite sides of dish; spray with cooking spray. In large microwave-safe bowl, heat 2 cups butterscotch morsels in microwave oven on high 1 minute 30 seconds or until melted, stirring every 30 seconds; stir in 1/2 tablespoon oil. Spread butterscotch mixture in prepared dish.
In separate large microwave-safe bowl, heat chocolate morsels in microwave oven on high 1 minute 30 seconds or until melted, stirring every 30 seconds; stir in pie spice and 1/2 tablespoon oil. Spread chocolate mixture over butterscotch mixture.
In medium microwave-safe bowl, heat remaining 1 cup butterscotch morsels in microwave oven on high 1 minute or until melted, stirring every 20 seconds; stir in remaining 1/2 tablespoon oil. Spread butterscotch mixture over chocolate mixture; with tip of small spatula, gently swirl butterscotch mixture into chocolate mixture to create marbled effect. Sprinkle butterscotch mixture with cherries, pretzels, pistachios and toffee bits; cover dish with plastic wrap and refrigerate 2 hours or until firm.
Use foil to lift bark from dish; remove foil and cut bark into 24 (3 x 1 1/2-inch) squares.
