Pre-heat oven to 180°C/160°C fan/350°F

Grease and line a 8"/20 cm square baking tin

In a small pan melt 50g of the peanut butter and the butter

Cool slightly

In a large mixing bowl add the melted peanut butter along with the sugars and mix well

Add vanilla and the egg

Add the flour, baking powder and chocolate chips

Transfer to the prepared baking tin and smooth

In a small saucepan melt the remaining 70g of peanut butter

Pour this over the top of the batter and swirl into the mixture

Bake 30-35 minutes or until a toothpick inserted into the middle comes out clean

Cool for about 10-15 minutes

When completely cook cut into 16 equal size squares (4x4)

Enjoy!