Peanut Butter Cups Fluff

• 6 cups Rice Krispies ceral • 6 tablespoons butter • 6 cups mini marshmallows , divided • 1 cup creamy peanut butter • Pinch salt • 7.5 ounce marshmallow fluff Prep a 9×13 baking pan with parchment paper so that the edges hang over the sides of the pan and then spray with nonstick spray. S