Preheat oven to 175C.

Line an 8x8 inch pan with aluminium foil and lightly grease.

In a mixing bowl a whisk together sugar and brown sugar.

Then add your cooled melted butter and egg.

Mix to combine.

Add in flour, and mix to combine.

Then fold in peanut butter chips.

And pour batter into prepared pan.

Drop dollops of nutella on top of the batter.

Use the back of a knife or a chopstick to create swirls.

Bake for 20-25 minutes until skewer comes out with a few moist crumbs or clean with no batter.

Allow to cool in pan before cutting.

Keep airtight at room temperature for up to a week.