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

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

Add the ½ cup melted unsalted butter to the cookie crumbs and process until the crumbs are evenly moistened and hold together when pressed.

Press the crumb mixture firmly and evenly into the bottom of the prepared 9×13 pan. Bake for 15 minutes, or until the crust is lightly golden. Remove from oven and set aside.

In a medium saucepan over medium–low heat, combine the 2 cups peanut butter chips, ⅔ cup light corn syrup, 4 tablespoons unsalted butter, and 1 teaspoon vanilla extract. Stir constantly until the mixture is fully melted and smooth, about 5 minutes. Remove from heat.

Spoon and spread ½ cup of the melted peanut mixture evenly over the hot baked crust.

Evenly sprinkle the 2 cups miniature marshmallows over the peanut layer. Return the pan to the oven and bake just until the marshmallows puff, about 1–2 minutes. Watch closely so the marshmallows do not brown. Remove from oven.

Add the 2 cups dry roasted peanuts and 2 cups crisp rice cereal to the remaining warm peanut mixture in the saucepan and stir until the peanuts and cereal are evenly coated. If the mixture becomes too thick to stir or spread, warm it briefly over very low heat just until loose again.

Drop spoonfuls of the peanut/peanut-butter-chip-coated peanut–cereal mixture over the marshmallow layer, then carefully spread and smooth with a non-stick spatula to cover the marshmallows as evenly as possible. If the mixture sticks to the spatula, spray the spatula lightly with non-stick cooking spray.

Let the bars cool completely at room temperature until set. Use the parchment to lift the slab from the pan and cut into bars.