Crush the Oreo cookies in a food processor or by hand.

Mix the crushed cookies with the melted butter.

Line a muffin pan with plastic wrap (you'll need 1-2 sheets), and press it down into each muffin cavity.

Divide the Oreo mixture evenly between the 12 muffin cavities, then press the mixture down to cover the bottom and about 1/3 to 1/2 way up each side to create a little well/ tart shell shape.

Place in the freezer while you make the filling.

In a large bowl beat the cream cheese until smooth using an electric mixer.

Beat in the powdered sugar and peanut butter.

Gently fold in the whipped topping until the mixture is even.

Spoon the mixture on top of each Oreo crust. Or spoon the mixture into a piping bag with a round tip (I used a 1M) or into a large, heavy duty ziploc bag and cut off the bottom corner. Then swirl it on top of each Oreo crust.

Place in the freezer to set for 30 minutes, or in the fridge to set for 2 hours.

Decorate each with a mini peanut butter cup, chopped peanuts or mini chocolate chips.