Adjust oven rack to lower-middle position and heat oven to 350 degrees. Grease a 9- by-13-inch rimmed baking sheet with vegetable cooking spray. Line pan bottom and up and over the long sides with heavy-duty foil for easy removal. Grease foil with vegetable cooking spray and then line with crackers, sugar side down, cutting as necessary to fit pan.
Heat butter and sugar in a small saucepan over medium heat, stirring frequently, until simmering. Pour mixture evenly over crackers and working quickly, use a spatula to spread it.
Bake until bubbly and golden brown, about 10 minutes. (Watch carefully to make sure it doesn’t burn) Remove from oven and sprinkle both white and dark chocolates over hot crackers; let stand a few minutes and the spread chocolate with the back end of a spoon (or finger if you can stand the heat) in figure eights, creating a marbleizing effect. Sprinkle with kisses. Freeze until firm.
Using foil handles, remove bar from pan. Break into pieces and serve.
Notes
If you can’t find the candy cane kisses in the store, substitute with 2 ounces of chopped white chocolate and crushed 12 peppermint candies (to do this, place in a sealed bag and crush with a rolling pin).
Recipe by Three Many Cooks at https://threemanycooks.com/recipes/sweet-treats/new-and-improved-peppermint-bark/