Mint-Chocolate Icebox Cake

INGREDIENTS

• 1 1/2 cups all-purpose flour
• 1 tablespoon instant coffee granules
• 1 1/2 teaspoons baking soda
• 1 1/4 cups unsweetened cocoa
• 1 cup Prune Purée, divided
• 1/2 cup water
• 3/4 teaspoon salt
• 1/4 teaspoon peppermint extract
• 1 (1-pound) box powdered sugar
• 3 eggs
• 3/4 cup boiling water
• Vegetable cooking spray
• 2 cups frozen reduced-calorie whipped topping, thawed