While these seem like a decadent treat to make for Halloween, the recipe is actually quite simple! It's a mixture of rice cereal, marshmallows, peanut butter, and chocolate candy! Super delicious!
Grease a 9 x 13-inch baking dish with softened butter and set aside.
In a 4-quart saucepan, melt the butter and peanut butter over medium heat, 4-6 minutes. Add the marshmallows and stir constantly until melted and smooth, 3-4 minutes.
Once melted, remove from the heat and add the Rice Krispies cereal. Stir until combined and slightly cooled, 1-2 minutes. Add the M&M candies and stir. Pour and press into the prepared baking dish.
Melt the white chocolate in the microwave, heating in 15-second increments, stirring in between each heating. Once all melted and smooth, add the food coloring of choice and drizzle over the bars.