Line an 8x8 inch square pan with parchment paper or foil and grease lightly.

Crush the cookies into fine crumbs using a food processor or rolling pin.

Mix cookie crumbs with 4 tbsp melted butter until combined. Press firmly into the bottom of the pan to form the crust. Freeze for 10 minutes.

In a microwave-safe bowl, combine peanut butter, chocolate chips, and 2 tbsp butter. Melt in 30-second intervals, stirring until smooth.

Stir in vanilla extract and salt.

Add the crispy rice cereal to the chocolate mixture and fold until evenly coated.

Pour the cereal mixture over the chilled crust and spread into an even layer.

Refrigerate for at least 1 hour until set. Lift out of the pan and cut into squares.