Step 1: Prepare the Biscuit Base

Crush 250g of plain chocolate cookies until they are nice and fine. You can use a food processor or place them in a bag and hit them with something heavy. Add 90g of melted butter to the crushed cookies and mix until well combined.

Step 2: Press the Base into a Pan

Lightly grease and line a standard slice pan (approximately 30cm x 20cm) with non-stick baking paper. Pour the biscuit mixture into the pan and use a flat-bottomed glass to press it down firmly and evenly across the entire surface. Place the pan in the fridge to chill while you prepare the filling.

Step 3: Prepare the Peanut Butter Filling

In a saucepan over medium heat, melt 90g of butter until it is nice, bubbly, and foamy. Add 1/2 cup of brown sugar, 1 1/2 cups of icing sugar (also known as powdered or confectioner's sugar), and 1 cup of thick, smooth peanut butter to the melted butter.

Step 4: Mix the Filling

Using a wooden spoon, mix all the ingredients in the saucepan together until they are melted and smooth. Turn off the heat once combined.

Step 5: Add Chocolate Chips to the Filling

Add 1/2 cup of dark chocolate chips to the peanut butter mixture and stir them through until evenly distributed.

Step 6: Spread the Filling

Retrieve the chilled cookie base from the fridge. Spread the peanut butter mixture evenly over the surface of the cookie crumbs. Return the pan to the fridge for 1 hour, or until the peanut butter mixture has set.

Step 7: Prepare the Chocolate Topping

Place 150g of good quality dark chocolate (broken into pieces) into a microwave-safe bowl. Microwave for about 15 to 20 seconds, then stir with a metal spoon. Continue microwaving in 20-second intervals, stirring after each, until the chocolate is completely melted and smooth.

Step 8: Apply the Chocolate Topping

Pour the melted chocolate over the set peanut butter layer. Use a spoon or spatula to smooth it out evenly across the entire surface. Pop the pan back into the fridge for about 10 to 15 minutes to allow the chocolate topping to set.

Step 9: Slice and Serve

Once the chocolate topping is set, lift the entire slice out of the pan using the baking paper. Carefully peel back the paper. Using a sharp knife, cut the large slice into smaller 2cm (1 inch) squares. Serve and enjoy!

• Use a smooth peanut butter that is not too oily to achieve the desired thick, caramel-like consistency for the filling.

• Dark chocolate helps to offset the sweetness of the peanut butter filling, creating a balanced flavor.

• Cut the squares into small 2cm (1 inch) pieces as they are quite rich.

• Use milk chocolate instead of dark chocolate for the topping if you prefer a sweeter flavor.

• Add chopped nuts (like peanuts or almonds) to the biscuit base or peanut butter filling for extra crunch.