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Rich, chewy Peanut Butter Brookies marry creamy peanut butter cookie dough with fudgy brownie batter for a snack that feels like a warm hug in every bite.
From the moment I first layered silky peanut butter on top of chocolatey batter, I knew these cookie bars would become my go-to treat. Brookies—half brownie, half cookie—are a playful twist on classic desserts, and adding peanut butter makes them perfect for bake sales, after-school snacks, or a cozy Friday night at home. I often serve these at family gatherings around the holidays, when everyone’s craving something a little decadent but homemade. At 50, I’ve learned that the simplest recipes can bring the biggest smiles, especially when they combine two great things into one.
Why You’ll Love This Recipe
• You get brownie and cookie in one—double the fun with half the fuss.
• Quick prep: no mixer needed, just a sturdy spoon and a mixing bowl.
• Crowd-pleasing flavors: peanut butter’s salty tang meets chocolate’s sweet richness.
• Perfect for gift boxes or cookie exchanges—slice and package with festive ribbon.
• Easily customize: swap nut butter, add mix-ins, or sprinkle flaky salt.
• Foolproof texture: fudgy center with slightly crisp edges every time.
• Family friendly: kids love helping swirl the batters together.
• Make-ahead magic: bake now, enjoy later—these bars improve after resting.
Ingredients
• ½ cup (115 g) unsalted butter, melted (use European-style for richness)
• 1 cup (200 g) granulated sugar
• 2 large eggs, at room temperature
• 1 teaspoon pure vanilla extract
• ½ cup (65 g) all-purpose flour (or 1:1 gluten-free blend)
• ¼ cup (30 g) unsweetened cocoa powder (Dutch-processed for depth)
• ½ teaspoon baking powder
• ¼ teaspoon fine sea salt
• ½ cup (130 g) creamy peanut butter (no-stir variety for easy swirling)
• 2 tablespoons powdered sugar (optional, for thicker swirl)
• ¼ cup chopped peanuts or peanut butter chips (for extra crunch)
Tips:
• Let your eggs sit out for 20 minutes before mixing so they blend more smoothly.
• If you prefer a sturdier swirl, mix peanut butter with powdered sugar until thick.
• For a darker chocolate base, add an extra tablespoon of cocoa.
Directions
1. Preheat and prep. Preheat your oven to 350°F (175°C). Line an 8×8-inch pan with parchment, leaving a slight overhang to lift the brookies out cleanly.
2. Mix the base. In a medium bowl, whisk melted butter and granulated sugar until glossy. Stir in eggs and vanilla until smooth—no lumps in sight.
3. Add dry ingredients. Sprinkle flour, cocoa powder, baking powder, and salt over the wet mix. Gently fold with a spatula until just combined; avoid overmixing or the brownies turn cakey.
4. Spread half the batter. Spoon half of the chocolate mixture into the prepared pan, smoothing it with the back of your spoon to the edges.
5. Prepare peanut swirl. In a small bowl, stir peanut butter with powdered sugar (if using) until creamy. Dollop evenly over the chocolate layer.
6. Top with chocolate. Drop remaining brownie batter over peanut butter in spoonfuls. Use a butter knife or skewer to swirl the two layers together—think marbled art, not muddy brown.
7. Add crunch. Scatter chopped peanuts or peanut butter chips on top for texture.
8. Bake to fudgy perfection. Bake 20–24 minutes, until the edges pull away slightly and a toothpick shows a few moist crumbs. Don’t overbake—these bars set as they cool.
9. Cool and chill. Let the brookies cool in the pan for 15 minutes, then transfer to the fridge for at least 30 minutes to firm up. This step makes slicing neat bars a breeze.
10. Slice and serve. Lift parchment out, slice into 12–16 squares with a sharp knife (wipe blade between cuts), and dig in.
Servings & Timing
Yield: Makes 12–16 cookie bars
Prep Time: 15 minutes
Bake Time: 20–24 minutes
Chill Time: 30 minutes
Total Time: About 1 hour
Variations
• Almond Butter Brookies: Swap peanut butter for almond butter for a nuttier twist.
• Peanut Butter & Jelly Brookies: Drop grape jelly atop the swirl before baking.
• Salted Caramel Brookies: Drizzle warm caramel sauce and sprinkle sea salt after baking.
• Espresso-Kissed Brookies: Add 1 teaspoon instant espresso powder to the batter.
• Chocolate Chunk Brookies: Fold in ½ cup chopped dark chocolate instead of chips.
• Vegan Brookies: Use flax eggs, dairy-free butter, and plant-based peanut butter.
Storage & Reheating
Store peanut butter brookies in an airtight container at room temperature for up to 3 days, or in the fridge for a week. For longer keeping, freeze in layers separated by parchment for up to 2 months—thaw in the fridge overnight. To refresh chilled bars, warm in a 300°F oven for 5 minutes or microwave a single square for 10 seconds to revive that gooey center.
Notes
I’ve learned that swirling the batters gently (not vigorously) gives the most eye-catching marbling. If your peanut butter is too stiff, warm it briefly in the microwave—10 seconds should do. A sprinkle of flaky sea salt right after baking brightens the flavors, so don’t skip it if you love that sweet-salty contrast. And yes, letting the bars chill is worth the extra wait; it creates neat edges and prevents crumble.
FAQs
Q: Can I use crunchy peanut butter?
A: Absolutely—you’ll end up with delightful peanut bits throughout the bars.
Q: Why are my brookies dry?
A: Overmixing or baking just a minute too long can dry them out; aim for a few moist crumbs on the toothpick.
Q: How do I make them gluten-free?
A: Substitute with a 1:1 gluten-free flour blend—most work beautifully here.
Q: Can I skip chilling?
A: You can, but the texture won’t be as tidy; chilling firms the layers and makes slicing cleaner.
Q: Is there a dairy-free option?
A: Swap in coconut oil or vegan butter and plant-based milk for a vegan-friendly batch.
Q: What’s the best way to slice neat bars?
A: Chill fully, then use a warm, sharp knife—dip it in hot water and wipe between cuts.
Q: Can I double the recipe?
A: Sure—just bake in a 9×13-inch pan and watch the timing (you may need a few extra minutes).
Q: How do I add more peanut butter flavor?
A: Stir 2 tablespoons of peanut butter into the chocolate batter before layering for an extra hit.
Conclusion
These Peanut Butter Brookies bring cookie-and-brownie lovers together in one delightful bar. They’re simple to whip up, endlessly adaptable, and always a crowd favorite. Give them a try, then pop back here to let me know how they turned out—or explore my other favorite cookie bars and brownie recipes for more sweet treats to bake and share!
Peanut Butter Brookies
Ingredients
- ½ cup (115 g) unsalted butter, melted (use European-style for richness)
- 1 cup (200 g) granulated sugar
- 1 teaspoon pure vanilla extract
- ½ cup (65 g) all-purpose flour (or 1:1 gluten-free blend)
- ¼ cup (30 g) unsweetened cocoa powder (Dutch-processed for depth)
- ½ teaspoon baking powder
- ¼ teaspoon fine sea salt
- ½ cup (130 g) creamy peanut butter (no-stir variety for easy swirling)
- 2 tablespoons powdered sugar (optional, for thicker swirl)
- ¼ cup chopped peanuts or peanut butter chips (for extra crunch)
Instructions
- Preheat your oven to 350°F (175°C). Line an 8×8-inch pan with parchment, leaving a slight overhang to lift the brookies out cleanly.
- In a medium bowl, whisk melted butter and granulated sugar until glossy. Stir in eggs and vanilla until smooth—no lumps in sight.
- Sprinkle flour, cocoa powder, baking powder, and salt over the wet mix. Gently fold with a spatula until just combined; avoid overmixing or the brownies turn cakey.
- Spoon half of the chocolate mixture into the prepared pan, smoothing it with the back of your spoon to the edges.
- In a small bowl, stir peanut butter with powdered sugar (if using) until creamy. Dollop evenly over the chocolate layer.
- Drop remaining brownie batter over peanut butter in spoonfuls. Use a butter knife or skewer to swirl the two layers together—think marbled art, not muddy brown.
- Scatter chopped peanuts or peanut butter chips on top for texture.
- Bake 20–24 minutes, until the edges pull away slightly and a toothpick shows a few moist crumbs. Don’t overbake—these bars set as they cool.
- Let the brookies cool in the pan for 15 minutes, then transfer to the fridge for at least 30 minutes to firm up. This step makes slicing neat bars a breeze.
- Lift parchment out, slice into 12–16 squares with a sharp knife (wipe blade between cuts), and dig in.
