Before you start
A fudgy one-bowl brownie base with ribbons of sweetened peanut butter dragged through the top. The swirl isn't just for looks: it bakes into soft, salty seams that cut the chocolate. Use standard smooth peanut butter, not the natural kind that splits.
Everything you need
- ⅔ cup (151 g) unsalted butter, melted
- 1¼ cups (250 g) granulated sugar
- ¾ cup (64 g) cocoa powder
- ¾ cup (94 g) all-purpose flour
- 2 large eggs
- 2 tsp vanilla extract
- ½ tsp fine salt
- ½ cup (128 g) smooth peanut butter
- 2 tbsp (15 g) powdered sugar
Weigh, don't scoop. Measuring flour by cups can overpack it and dry out your bake. Tap any ingredient to open its converter.
Method
-
Heat the oven to 175°C / 350°F. Line a 20 cm (8-inch) square tin with baking paper, leaving an overhang.
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Whisk the melted butter with the granulated sugar and cocoa until glossy. Whisk in the eggs one at a time, then the vanilla, and keep whisking for a minute for a shiny top.
For this step
- ⅔ cup (151 g) unsalted butter
- 1¼ cups (250 g) granulated sugar
- ¾ cup (64 g) cocoa powder
- 2 large eggs
- 2 tsp vanilla extract
- ½ cup (128 g) smooth peanut butter
- 2 tbsp (15 g) powdered sugar
-
Fold in the flour and salt with a spatula, stopping the moment the flour disappears. Overmixing makes brownies cakey.
For this step
- ¾ cup (94 g) all-purpose flour
- ½ tsp fine salt
-
Spread the batter in the tin. Warm the peanut butter for 20 seconds and stir in the powdered sugar until pourable.
For this step
- ⅔ cup (151 g) unsalted butter
- 1¼ cups (250 g) granulated sugar
- ¾ cup (64 g) cocoa powder
- ½ cup (128 g) smooth peanut butter
- 2 tbsp (15 g) powdered sugar
-
Dot the peanut butter over the batter in spoonfuls, then drag a knife through it in an S shape a few times. Two or three passes is plenty, more and the swirl turns muddy.
For this step
- ⅔ cup (151 g) unsalted butter
- ½ cup (128 g) smooth peanut butter
-
Bake for 28 to 34 minutes, until the edges are set and a skewer in the middle comes out with moist crumbs. Cool completely in the tin before lifting out and cutting.
Baker's tips
- Cool them fully, ideally a couple of hours. Warm brownies tear instead of slicing cleanly.
- Flaky salt over the peanut butter just before baking makes both flavours sharper.
Make it your own
- Swap the peanut butter for biscoff, tahini or almond butter, same quantity.
- Press 100 g chocolate chunks into the top before baking for a heavier hit.
Storing & freezing
Airtight at room temperature for 4 days, and they get fudgier on day two. Freeze cut squares for 3 months.
Frequently asked
How many grams is a cup of peanut butter?
About 256 g per US cup, so the ½ cup here is roughly 128 g. The peanut butter converter will rescale it for you.
Can I use natural peanut butter?
It works but the oil can separate and leave greasy patches. Stir it very well first, or use a standard emulsified peanut butter for a cleaner swirl.
Baking in a different unit? Use the cups ↔ grams converter or the recipe scaler to halve or double this recipe.
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A note on cooking safely. Recipes are provided for informational purposes only and are not medical or nutritional advice. Cooking times, temperatures and quantities are suggestions: use your own judgement, and check that meat, poultry, fish and eggs are properly cooked before serving.
Consult a qualified healthcare professional before making dietary changes, particularly if you have allergies, a medical condition or specific nutritional requirements.