Preparation Notes: plus cooling
Serving notes: Cuts into 16 (or fewer larger pieces!)
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- 175 g butter, chopped, plus extra to grease
- 125 g dark chocolate, roughly chopped
- 250 g light brown soft sugar
- 2 medium eggs
- 125 g plain flour
- 25 g cocoa powder
For the peanut butter marble
- 25 g unsalted butter, melted
- 40 g icing sugar, sifted
- 100 g smooth peanut butter
- 1/2 tsp vanilla extract
- Step 1
Preheat oven to 180°C (160°C fan) mark 4. Grease and line a 20.5cm (8in) square tin with baking parchment. To make the brownie, melt butter and chocolate (stirring frequently) in a large pan until melted and smooth. Take off the heat and stir in sugar, then the eggs. Sift over the flour and cocoa powder and mix to combine. Set aside.
- Step 2
In a medium bowl, mix together the ingredients for the peanut butter marble.
- Step 3
Spoon about one-third of the chocolate mixture into the tin and spread to level. Dollop over a few spoonfuls of peanut mixture. Top with remaining chocolate mixture and spread to level. Drop more peanut spoonfuls on top, then tap the tin down firmly on a surface to release any air bubbles. Finally, run a knife or skewer through the mixture to marble it.
- Step 4
Bake for 35min until a solid crust has formed. Leave to cool completely in tin before lifting out. Slice.
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To store
Keep well wrapped at room temperature for up to 10 days (keeps better in a single piece).Per Serving:
- Calories: 274
- Total carbs: 30 g
- Sugars: 24 g
- Total fat: 17 g
- Saturated fat: 9 g

The GH Kitchen Team are Good Housekeeping’s resident recipe developers and all-round food obsessives. GH Kitchen Director Sarah Akhurst is our resident hosting pro and loves nothing more than putting on a foodie feast for friends. Our GH Kitchen Manager Linzi Pucino is our very own Italian food expert (originally hailing from the North East of Scotland!) and can be found working her way through midweek recipes that cover all bases, from haggis to ragu! Our Kitchen Editor Nadine Brown loves digging into the stories behind her favourite foods and enjoys applying her eclectic tastes to more modern, flavour-forward recipes - just don't give her too much chilli! Our Junior Food Content Produce Frankie Prichard combines a love of beautiful presentation and flavour-led, seasonal cooking in her recipe development, along with a passion for bringing people together through food. With a wealth of professional kitchen experience between them, they’re dedicated to ensuring every Good Housekeeping recipe is the best it can be, so you can trust they’ll work every single time
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