Pre-heat the oven to 170°C/ 150°C/ Gas Mark 3. Grease and line an 8” square cake tin.

Place the butter and sugar into a bowl and cream together, once smooth add the egg yolk and Vanilla Extract and mix together.

Stir in the flour and Baking powder to form a biscuit dough. Finally stir in the Chocolate Chunks.

Once you have a smooth dough, tip into your prepared tin and press to cover the base in an even layer of cookie dough. Place the cookie dough baser in the oven for 10 minutes - it will still be soft and gooey but it will continue baking once the brownie layer is added. Remove from the oven and top with a layer of oreos and then pour the caramel on top. 

Whilst the cookie dough is baking, make the brownie mixture. Break the chocolate into pieces and place in a saucepan. Add the butter and sugar and gently heat, stirring continuously until the mixture is melted. Leave to cool for 10 minutes. 

Once cooled mix in the eggs to make a thick glossy mixture. Sieve the flour and Baking Powder on top and mix together until well incorporated. 

Pour the brownie mixture on top of the caramel layer and sprinkle with the Chocolate Chunks. If you have any leftover oreos break up and sprinkle on top of the brownie mix.

Place in the oven and bake for 30 minutes until the brownie is risen and firm to touch around the edge – the brownie might be slightly gooey in the middle but it will firm up at it cools.  

For extra indulgence, drizzle any leftover caramel over the brownie when serving!