Preheat the oven to 180ºC/160ºC fan.

Add together in a bowl butter (100g), caster sugar (100g) and light brown sugar (80g), and beat until you have a fluffy mixture.

Add 1 egg, lightly beaten, into the mixture

Add 1 tsp of vanilla extract

Add ½ tsp of salt, sprinkled evenly across the mixture.

Sift in 180g of self-raising flour, and beat the mixture until it is fully combined.

Add in 40g of chocolate chips.

Add in 50g of peanut butter.

Mix all the ingredients together until there is an even distribution of chocolate chips and peanut butter across the mixture.

Spoon the mixture onto baking paper. For neat looking cookies, the mixture for each cookie should be roughly 2cm high and 6cm wide in a circular shape with sufficient space either side to allow it to widen to about 12cm when cooked.

Place into the oven for 8 to 10 minutes, depending on how crisp you like the outside of your cookie to be.

Once taken out of the oven allow the cookies to rest in the baking tray for five minutes whilst they harden, before moving to a wire rack to cool.