Line a 20cm (8”) square baking tin with baking paper or tinfoil making sure it goes up the sides with some overhang.
In a food processor crush the Oreos until they are fine crumbs. Add the melted butter and stir well to combine.
Press firmly into the prepared tin using a glass or your hands. Put in the fridge to set while you make the filling.
Add the cream cheese & peanut butter to the bowl of a stand mixer and mix on high speed using the paddle attachment until smooth and fluffy (about 5 minutes). Add the sugar, cream and vanilla and mix on medium speed for a further 3 or 4 minutes until combined and smooth.
Spread the filling onto the base and smooth using a spatula. Sprinkle with chopped peanut butter cups and put in the fridge to set for at least 4 hours or overnight.
Using the baking paper or tinfoil, lift the cheesecake out of the tin to cut. Use a sharp knife to cut into pieces. To ensure clean cuts I like to wipe the knife with a paper towel between cuts.
Serve from the fridge with a drizzle of chocolate sauce and more peanut butter cups.