A dense, fudgy sheet-pan brownie swirled with peanut butter and raspberry jam, these PB&J brownies make forty squares from one pan — which is exactly the point, because they’re built for a crowd.
Three tablespoons of instant coffee granules go into the batter. You won’t taste coffee; you’ll taste more chocolate. It’s the single most effective thing you can do to a brownie recipe, and it costs nothing.
Why You’ll Love These PB&J Brownies
This is a big-batch recipe that behaves itself, as long as you respect two instructions.
- Forty brownies from one pan: A 12 by 18 inch sheet pan, so it covers a party or a bake sale in one bake.
- Coffee deepens the chocolate: Instant granules dissolve into the batter and amplify the cocoa without tasting of coffee.
- Three kinds of chocolate: Semisweet chips melted in, unsweetened for depth, and more chips tossed through whole.
- Real peanut crunch: Roasted salted peanuts folded in, plus the peanut butter swirl on top.
- Raspberry cuts the richness: Jam thinned with a spoonful of water so it swirls instead of sitting in lumps.
- Fudgy, not cakey: Chilled before cutting, which is what gives them clean edges and a dense bite.
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Ingredient Notes
A long list for a big pan, but nothing unusual. Exact amounts are in the recipe card below.
- Unsalted butter: A full pound. This is a sheet pan of brownies, not a small tray.
- Semisweet chocolate chips: One pound melted into the base, eight more ounces tossed through the batter whole.
- Unsweetened chocolate: Six ounces. It’s what keeps the sweetness in check.
- Instant coffee granules: Three tablespoons. Granules, not brewed coffee — you don’t want the extra liquid.
- Flour, divided: One cup in the batter, a quarter cup for tossing the chips and peanuts so they don’t sink.
- Roasted salted peanuts: Roughly chopped. Salted is deliberate; it plays against the jam.
- Smooth peanut butter: Spooned over the top for swirling. Smooth, not crunchy — the peanuts are already in the batter.
- Raspberry jam: Loosened with a tablespoon of water so it ribbons through rather than clumping.
You need a 12 by 18 by 1½ inch sheet pan, a heatproof bowl for melting over simmering water, and a knife for swirling.
How To Make PB&J Brownies
Two instructions matter more than the rest: stir rather than beat, and don’t overbake.
- Heat the oven to 350 degrees F and butter and flour a 12 by 18 by 1½ inch sheet pan.
- Melt the butter, 1 pound of chips and the unsweetened chocolate over simmering water, then let it cool slightly.
- In a large bowl, stir — do not beat — the eggs, coffee granules, vanilla and sugar together.
- Stir the warm chocolate into the egg mixture and let it cool to room temperature.
- Sift 1 cup flour with the baking powder and salt, then fold into the cooled chocolate mixture.
- Toss the remaining 8 ounces of chips and the peanuts with 1/4 cup flour, then fold them in.
- Pour into the pan. Spoon the peanut butter and the loosened jam over the top and swirl through with a knife.
- Bake 20 minutes, then rap the pan against the oven shelf to release trapped air.
- Bake another 10 to 15 minutes, until a toothpick comes out clean. Cool thoroughly, refrigerate, then cut.
This makes about 40 brownies. Beating rather than stirring the eggs is the classic mistake — it whips in air and turns a fudgy brownie cakey.
Storage Options
Brownies this dense keep well and travel well.
- Room temperature: airtight for up to 4 days.
- Fridge: up to 1 week. Chilling is also how you get clean cuts in the first place.
- Freezer: wrap cut squares individually for up to 3 months.
- Let frozen brownies come to room temperature rather than microwaving, which makes them oily.
Variations and Substitutions
The base is a classic sheet-pan brownie, so the swirl is where you can play.
- Swap raspberry jam for strawberry, cherry or blackberry.
- Use almond or cashew butter instead of peanut butter, and match the nuts.
- Leave out the nuts entirely for a smoother, purely swirled brownie.
- Halve everything and bake in a 9 by 13 pan, checking 5 minutes earlier.
- Scatter flaky salt over the top before baking to sharpen the whole thing.
What to Serve with PB&J Brownies
They’re very rich, so anything alongside should be plain and cold.
- Cold milk, which is the honest answer.
- Vanilla ice cream, while the brownie is slightly warm.
- Fresh raspberries, echoing the jam.
- Strong black coffee, which the batter is already nodding to.
- Cut small for a dessert table — a full square is a lot.
Here’s what comes up most often.
Frequently Asked Questions
Why stir the eggs instead of beating them?
Beating incorporates air, and air makes brownies rise and set cakey. Stirring keeps the batter dense, which is what gives you that fudgy, slightly chewy texture. It’s the same reason the recipe has you rap the pan against the shelf partway through baking — you’re actively trying to get air out, not in.
Can I halve the recipe?
Yes. Halve everything and use a 9 by 13 inch pan. Start checking at around 25 minutes total, since a smaller, slightly deeper pan behaves a little differently. Everything else about the method stays the same, including the rap against the shelf at the twenty-minute mark.
Why toss the chips and peanuts in flour?
So they stay suspended. Without that light coating of flour, the chips and nuts sink through the batter as it bakes and end up in a dense layer at the bottom. A quarter cup is enough to give them just enough grip on the batter around them.
Do I have to refrigerate before cutting?
If you want clean edges, yes. Warm brownies tear and smear, and the peanut butter swirl drags across the top of every square. An hour in the fridge firms them enough to cut cleanly with a long knife, wiped between cuts. They can come back to room temperature before serving.
For another crowd-sized bake, try my butterscotch cookies.
PB&J Brownies
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Ingredients
- 1 pound unsalted butter
- 1 pound + 8 ounces semisweet chocolate chips divided
- 6 ounces unsweetened chocolate
- 8 large eggs
- 3 tablespoons instant coffee granules
- 2 tablespoons vanilla extract
- 2 cups granulated sugar
- 1 1/4 cups flour divided
- 1 tablespoon baking powder
- 1 teaspoon coarse salt
- 1/2 cup roughly chopped roasted salted peanuts
- 1 cup smooth peanut butter
- 1/3 cup raspberry jam mixed with 1 tablespoon water
Instructions
- Preheat the oven to 350 degrees F. Butter and flour a 12 by 18 by 1 1/2-inch sheet pan.
- Melt together the butter, 1 pound of chocolate chips, and the unsweetened chocolate in a medium bowl over simmering water. Allow to cool slightly. In a large bowl, stir (do not beat) together the eggs, coffee granules, vanilla and sugar. Stir the warm chocolate mixture into the egg mixture and allow to cool to room temperature.
- In a medium bowl, sift together 1 cup of flour, the baking powder, and salt. Add to the cooled chocolate mixture. Toss the remaining 8 ounces of chocolate chips and peanuts in a medium bowl with 1/4 cup of flour, then add them to the chocolate batter. Pour into the prepared sheet pan. Spoon the peanut butter and jam mixture over the top of the chocolate mixture and using a knife, swirl it through the chocolate mixture.
- Bake for 20 minutes, then rap the baking sheet against the oven shelf to force the air to escape from between the pan and the brownie dough. Bake for about 10 to 15 minutes more or until a toothpick comes out clean. Do not overbake! Allow to cool thoroughly, refrigerate*, and cut into squares.