Peanut butter brownie

Photographer: Kate
Serves 12

One of the side effects of being both a scientist and foodie is that ideas and inspiration sometimes come about in the most unexpected of ways.  This peanut butter brownie recipe (loosely based on one from BBC Good Food) is one I first made for “work purposes” in my previous life as an ice cream scientist. There are national ice cream awards held once a year and the whole R&D team traditionally devotes some extra time to the product development lab, mixing and concocting flavours which normally would not be able to be made under usual factory production constraints. Peanut butter brownie ice cream- now, who wouldn’t be interested in a scoop of that?

For me (and I’m sure for this is also true for many others), peanut butter is like the lifeblood which runs through childhood, making an appearance in school sandwiches, homemade cookies, and of course even as the quintessential sprinkle as chopped nuts for those ice cream sundaes. Naturally, as a twenty-something adult who missed the carefree lifestyle of days past (and also literally faced with a 10kg sample bucket of peanut butter in the lab), I jumped at the chance to bring the two together.

And in case you’re wondering about the science behind those delicious aromas of chocolate, peanut butter and overall sweet fudgy goodness coming out of the oven? That’s the Maillard Reaction. The heat causes a reaction between carbohydrates (sugars) and the proteins in these brownie ingredients, producing hundreds of different flavour compounds which give these brownies not only a complex depth of flavour but also the irresistible aroma reminding you that your brownies are almost done.

I’d say that these brownies can be eaten with a cup of tea or coffee but are best served chopped up and swirled through good quality vanilla ice cream with chocolate sauce. And yes, that is my “professional” opinion.



250g crunchy peanut butter
200g dark chocolate (70% cocoa solids)
240g brown sugar
3 medium eggs
100g self-raising flour


1. Preheat the oven to 180°C Bake or 160°C Fan Bake and line a 20cm square baking tin with baking paper.
2. Reserve 50g each of the peanut butter and dark chocolate.
In a saucepan, melt the remaining peanut butter and dark chocolate together with all the brown sugar over a low heat, until the sugar has just dissolved. Stir constantly to avoid burning the sugar.
3. Once melted, remove from the heat and using a wooden spoon, beat in the eggs one by one. Sift in the flour and scrape the brownie mix into the tin.
4. Take the reserved peanut butter and microwave on high for 45 seconds (or melt in a saucepan) until the consistency becomes soft and runny. Drizzle this over the brownie, using a fork to create a swirl pattern over the surface.
5. Bake the brownie for approximately 20-25 minutes until it has risen and a crust has formed, but the middle still seems uncooked (you can test this by inserting a wooden skewer).
6. Melt the reserved chocolate and using a fork, drizzle this over the brownie. Cool in the tin before cutting into squares.