Step 1

Preparation Preheat the oven to 180°C (350°F), Gas Mark 4. Lightly grease a 13x9" baking tin and line with a piece of parchment paper that overhangs the two long sides. Secure in place with metal clips.

Step 2

For the peanut butter cookie layer, mix the peanut butter and brown sugar together in a large bowl for a couple of minutes until combined and slightly lightened. Add the egg and egg yolks and beat together for a further 2–3 minutes. Add all the remaining ingredients (reserving 3 tablespoons of the peanuts for sprinkling over later) and gently mix together to form a uniform cookie dough. Spread the cookie dough in an even layer in the prepared tin, then set aside.

Step 3

For the brownie layer, add the butter and cocoa to a small saucepan over a medium heat, stirring constantly, until melted and smooth. Remove from the heat and set aside. Place the sugars, salt, vanilla and eggs in a large bowl and whisk together with an electric mixer for 2–3 minutes or until slightly thickened and pale. Pour in the melted butter mixture, mixing briefly until combined, then fold in the flour. Pour the batter over the cookie layer and spread into an even layer, then sprinkle over the reserved peanuts.

Step 4

Bake for about 25–30 minutes, or until a skewer inserted into the middle comes out with a few moist crumbs.

Step 5

Leave the brookies to cool completely in the tin, before using the parchment paper to lift them from the tin and cutting into squares.Store in a sealed container for 3–4 days.

Step 6

Reprinted with permission from One Tin Bakes by Edd Kimber, copyright © 2020. Photographs by Edd Kimber. Published by Kyle Books.

Step 7

Buy the full book from Amazon.