1. Preheat the oven to 350°F.
2. Mix the ground flax seed with the water and let sit for 2-3 minutes.
3. In a large bowl, combine the cookie mix, ½ cup of JUSTIN’S® Classic Peanut Butter, water, banana, and flax mixture. Stir until fully combined.
4. Press the cookie dough into the bottom of a 9 x 13-inch jelly roll pan.
5. Bake for 10-14 minutes or until golden brown.
6. Temporarily remove from the oven and, while still warm, spread the remaining ¼ cup of JUSTIN’S® Classic Peanut Butter over the bars and sprinkle with chopped JUSTIN’S® Mini Dark Chocolate Peanut Butter Cups.
7. If using large marshmallows, cut each marshmallow in half vertically. (Mini marshmallows will work here too. No need to cut them in half).
8. Line the marshmallows on top of the peanut butter cups and press down slightly.
9. Place the pan back in the oven and broil for 1 minute or less (watch closely!) until the marshmallows are the perfect golden brown.
10. Slice ’em up and enjoy! Warning. They are messy and addicting.