Preheat oven to 350°F. Line a 9×13-inch baking pan with parchment paper and lightly spray the parchment with non-stick cooking spray.

Place the 16 ounces peanut butter sandwich cookies in a food processor and pulse until fine crumbs form.

Add the ½ cup unsalted butter (melted) to the cookie crumbs and process until the crumbs clump together.

Press the crumb mixture evenly into the bottom of the prepared 9×13 pan. Bake for 15 minutes or until the crust is golden brown. Remove from oven and leave oven on.

While the crust bakes, combine 2 cups peanut butter chips, ⅔ cup light corn syrup, 4 tablespoons unsalted butter, and 1 teaspoon vanilla extract in a medium saucepan. Cook over medium-low heat, stirring, until the mixture is smooth, about 5 minutes. Remove from heat.

Measure and spread ½ cup of the melted peanut mixture evenly over the hot baked crumb base.

Evenly sprinkle 2 cups miniature marshmallows over the layer from step 6. Return the pan to the oven and bake just until the marshmallows puff up, about 2 minutes. Do not let the marshmallows brown. Remove the pan from the oven.

To the remaining peanut mixture in the saucepan, add 2 cups dry roasted peanuts and 2 cups crisp rice cereal. Stir until the peanuts and cereal are evenly coated.

Working while the topping is warm, drop spoonfuls of the peanut/peanut-butter-chip mixture over the marshmallow layer and carefully spread to cover as evenly as possible using a non-stick silicone spatula. If the mixture sticks to the spatula, lightly spray the spatula with non-stick cooking spray and continue spreading.

Let the bars cool completely in the pan before cutting into bars.