Stiff Peaks

An indulgent journey into baking

Peanut Butter Brownie

Thanks Buzfeed! So, inspiration is a tricky thing for me. Sometimes baking ideas will come from random discussions with friends, other times through cravings, but mostly inspiration will come from the internet. And this week’s recipe comes from Buzzfeed’s Truly Magnificent Peanut Butter Desserts.

peanut butter brownie

As it happens, this recipe is an adaptation from an adaptation from an adaptation, but all in US imperial measurements, so this should be the first interpretation in metric…


  • 140g unsalted butter (softened)
  • 225g golden caster sugar
  • 100g cocoa powder
  • 2 large eggs
  • 1/4tsp salt
  • 1/2tsp vanilla extract
  • 62g plain flour

Peanut Butter Icing

  • 85g unsalted butter (softened)
  • 190g smooth peanut butter
  • 125g icing sugar
  • Maldon sea salt


  • 20cm square cake tin or equivalent area rectangular tin
  • baking parchment
  • saucepan
  • oven preheated to 170ยบ celsius


First you’ll want to grease and line your tin and preheat your oven to 170 celsius, as it won’t take long to prepare the brownie mixture.

I’ve not quite made brownie like this before, I think I blame the Americans. Anyway, so we’ll start by taking our softened butter and placing it in a glass/pyrex bowl above a pan of simmering water (a bain-marie) making sure that the bowl does does not touch the water. Add to that the sugar, salt, and cocoa and stir until the butter just about starts to melt. You don’t want to let this mixture get too warm, as you’ll be adding your eggs directly to it. Take the bowl off the pan and stir more vigorously until the mixture becomes smooth. It should be warm to touch but not hot. If you can’t hold the sides of the bowl, let the mixture cool a little before the next step.

Once your chocolate mixture is cool enough, add your eggs one at a time, making sure you stir until the egg is well combined. Add in the vanilla extract and then sift over the flour. Fold in the flour, making sure not to over-mix. You’ll want a smooth consistent mixture, without pockets of flour if possible.

Pour the mixture into your prepared tin and spread evenly. There’s no raising agent in the brownie, and it’s a pretty thick mixture, so you’ll want to make it as even as possible in the tin. Bake for 20 to 25 minutes until a toothpick comes out clean. Allow the brownie to cool completely in the tin.

Once your brownie is cool, we can start on the icing. This will be a very thick and sticky mixture because of the peanut butter, so be careful of your arms or any electric equipment you want to use. I mixed everything manually with a flexible silicon spatula (and I still broke the spatula by the end of it!). Cream together the butter and peanut butter until well combined and there are no identifiable lumps of butter. To this mixture, gradually add your icing sugar a few tablespoons at a time. Once well whipped and combined, spread the mixture over your cold brownie, using a palette knife or offset spatula if you want a nice flat surface. This bit isn’t very easy because of how sticky the icing is, but have patience and persevere! Sprinkle with some Maldon sea salt to taste.

Cover with foil still in the tin, and chill the brownie in the fridge overnight before attempting to cut. If you cut it immediately, the icing will be too soft and make a mess. Remove the brownie from the tin after it has been chilled for at least 4 hours and use a large knife to cut the brownie into squares or triangles. You’ll want to heat your knife under some hot water and wipe clean between each slice. This will ensure a clean edge.