First up, preheat your oven to 200°C/180°C fan oven/Gas mark 6 and line a 10”x8” baking tin with baking parchment.

Next up, cream together the butter and sugar in a large bowl until pale and creamy. Pop in the egg yolk and Vanilla Extract and mix until smooth.

Sieve over the flour and Baking Powder and mix until a dough begins to form. Pour in the all the White Chocolate Chunks and most of the Milk and Extra Dark Chocolate Chunks, keeping a handful aside for later. Mix through the chocolate chunks until all combined.

Pop your cookie dough into your prepared tin and press down into the tin to create an even layer. Sprinkle over the reserved Chocolate Chunks and pop into the oven to bake for 20-25 minutes, until golden, your cookie dough will firm up as it cools. Leave to cool in the tin for 20 minutes, then pop on to a wire rack to cool completely. Alternatively serve warm with a dollop of ice-cream!