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Peanut Butter Brownies are the fudgy, over the top treat that hide a whole layer of melty peanut butter cups inside and get crowned with the fluffiest peanut butter frosting, and I first made them one rainy afternoon when Maddie decided we needed the most chocolate and peanut butter dessert possible. If you love an easy chocolate peanut butter mashup like our Reeses peanut butter cup cookies, these stuffed brownies take it to a whole new level.
You start with a boxed brownie mix and a frosting you whip yourself, so these taste totally from scratch with barely any effort.
Peanut Butter Brownies Quick Look
- 🕒 Prep Time: 10 minutes
- 🌡️ Cook Time: 30 minutes
- ⏳ Total Time: 40 minutes
- 🍽️ Serving: 15 brownies
- ⚡ Calories: 304kcal
- 🌶️ Flavor Profile: Rich fudgy chocolate with sweet, salty peanut butter
- ✋ Difficulty: Easy, on par with our chocolate poke cake
Quick Answer
Make Peanut Butter Brownies by spreading two thirds of a prepared brownie batter into a parchment lined pan, pressing in a layer of peanut butter cups, then covering with the rest of the batter. Bake at 350 degrees F for 25 to 30 minutes, cool completely, then top with a whipped peanut butter frosting and slice into squares.
Jump to:
- Peanut Butter Brownies Quick Look
- Quick Answer
- Why This Recipe Works
- Why You’ll Love This Recipe
- Key Ingredients
- Variations and Substitutions
- How to Make Peanut Butter Brownies
- Recipe Tips & Tricks
- Serving Ideas and Suggestions
- Peanut Butter Brownies FAQs
- Other Recommended Brownie and Bar Recipes
- Peanut Butter Brownies
Why This Recipe Works
Click to see the technique science
- A boxed mix keeps it foolproof. Starting with a brownie mix gives you a reliably fudgy base every time, so you can focus on the fun peanut butter layers.
- The stuffed center is the magic. A hidden layer of peanut butter cups melts into the brownies as they bake, leaving gooey pockets in every square.
- Whipped frosting tastes homemade. Beating peanut butter, butter, and cream for two minutes makes a frosting so light it tastes like you made it from scratch.
- Parchment makes them easy to lift. Lining the pan lets you lift the whole slab out and cut clean squares with no sticking.
- Chocolate and peanut butter never miss. The salty sweet combo is a guaranteed crowd favorite that disappears fast at any party.
Why You’ll Love This Recipe
- These Peanut Butter Brownies are rich, fudgy, and stuffed with a melty peanut butter cup surprise in every bite.
- They start with easy boxed shortcuts, so they come together fast for a last minute treat.
- They are an absolute crowd favorite and pair perfectly with a scoop of our no churn cookie dough ice cream.
Key Ingredients
Here is what makes these Peanut Butter Brownies work, and why each piece matters.
- Brownie mix: a fudgy boxed mix is the shortcut base, just grab the eggs, oil, and water it calls for.
- Peanut butter cups: a full layer of cups stuffed in the middle is what makes these brownies special.
- Creamy peanut butter: use a no stir creamy peanut butter for the smoothest, fluffiest frosting.
- Heavy cream: a splash whipped into the frosting makes it light and spreadable instead of dense.
- Powdered sugar: it sweetens and stabilizes the frosting, the same way it does in our chocolate cream cheese frosting.
See recipe card for exact quantities.
Variations and Substitutions
These Peanut Butter Brownies are easy to make your own.
- Use a homemade brownie batter instead of boxed if you prefer a from scratch base.
- Swap the peanut butter cups for chopped peanut butter eggs or mini cups, or add a handful of chocolate chips.
- Top with extra chopped peanut butter cups, a chocolate drizzle, or flaky sea salt.
- Turn them into a sundae base, like we do with our red velvet cookies and cream brownies.
How to Make Peanut Butter Brownies
- Mix the brownie batter. Prepare the brownie mix according to the box, then spread about two thirds of it into a parchment lined 9×13 pan.
- Stuff with peanut butter cups. Press a full layer of peanut butter cups into the batter, then gently spread the remaining batter over the top to cover them.
- Bake the brownies. Bake at 350 degrees F for 25 to 30 minutes until a toothpick comes out with a few moist crumbs, then cool completely.
- Start the frosting. Beat the creamy peanut butter and softened butter together until smooth and combined.
- Whip it fluffy. Add the powdered sugar a little at a time, then the heavy cream and vanilla, and whip for two minutes until light and fluffy.
- Frost and slice. Lift the brownies out with the parchment, spread the peanut butter frosting evenly over the top, and slice into squares.
Recipe Tips & Tricks
- Do not overbake. Pull the brownies when a few moist crumbs cling to the toothpick for the fudgiest texture.
- Cover the cups completely. Make sure the top batter seals in the peanut butter cups so they melt inside instead of burning.
- Cool fully before frosting. Warm brownies will melt the peanut butter frosting into a slippery mess.
- Use room temperature butter. Softened butter whips into the frosting smoothly with no lumps.
- Line the pan with parchment. It makes lifting and slicing clean and easy.
- Chill for neat squares. A short chill firms up the frosting so your cuts stay sharp.
Serving Ideas and Suggestions
These Peanut Butter Brownies are rich enough to stand on their own, but they are even better with a cold glass of milk or a scoop of vanilla ice cream.
Pile them on a dessert tray next to our cosmic brownie cookies and butterfinger brownies for an over the top chocolate spread.
They are perfect for bake sales, potlucks, and birthday parties, and they travel well since they hold their shape once chilled. For another candy stuffed favorite, try our easy Oreo dirt cake.
Peanut Butter Brownies FAQs
Yes, bake the Peanut Butter Brownies up to two days ahead and store them covered. Frost them the day you serve, or frost ahead and keep them chilled until party time.
Store Peanut Butter Brownies in an airtight container at room temperature for up to three days, or in the fridge for up to a week. Bring them to room temperature for the softest texture.
Absolutely. Freeze the brownies, frosted or unfrosted, in an airtight container for up to three months. Thaw at room temperature before serving.
Any boxed fudge brownie mix works for Peanut Butter Brownies. A 9×13 family size mix fits this recipe perfectly and gives you thick, fudgy bars.
Yes, swap the peanut butter cups in these Peanut Butter Brownies for chopped candy bars, mini cups, or peanut butter eggs depending on the season.
If the frosting on your Peanut Butter Brownies is too thick, whip in another tablespoon of heavy cream at a time until it reaches a light, spreadable consistency.
Craving more chocolate and peanut butter? Try our Reeses peanut butter cup cookies next.
Drizzle these with our homemade hot fudge sauce for an over the top chocolate treat.
For a colorful chocolate treat the kids love, bake a batch of our cosmic brownies.
Peanut Butter Brownies
Ingredients
For the brownies:
For the frosting:
- 3/4 cup creamy peanut butter
- 1/2 cup unsalted butter softened
- 2 & 1/4 cups powdered sugar
- 4 tablespoons heavy cream
- 1 & 1/2 teaspoons vanilla extract
Instructions
- Preheat the oven to 350°F. Line a 9×13 baking dish with parchment paper, set aside.
- In a large bowl, mix the brownie mix with the ingredients listed on the back of the box. Spread about ⅔ of the batter into the prepared baking dish.1 box brownie mix + ingredients needed on the package
- Place 15 Reese cups on top of the batter, and press them in slightly.15 full-sized Reese’s Cups
- Gently spread the remaining batter on top of the layer of peanut butter cups, ensuring they are completely covered with batter.
- Bake for 25-30 minutes until a toothpick inserted into the center of the brownie comes out mostly clean; a few moist crumbs are okay, but any wet batter and it needs to bake longer.
- Place on a wire rack to cool completely.
- Once the brownies have cooled, make the frosting by placing the peanut butter and butter into a large bowl with an electric hand mixer or stand mixer with the paddle attachment. Cream until smooth.3/4 cup creamy peanut butter, 1/2 cup unsalted butter
- Add the powdered sugar in a little at a time until fully mixed in; scrape the sides as needed. The mixture will be thick.2 & 1/4 cups powdered sugar
- Add the heavy cream and vanilla, and stir it until combined. Place the mixer on medium-high speed and whip for 2 minutes until light and fluffy.4 tablespoons heavy cream, 1 & 1/2 teaspoons vanilla extract
- Using the parchment paper to help, lift the brownies out of the baking dish.
- Spread the frosting evenly over the top of the brownies. Serve immediately or add more fun toppings if desired.
Notes
- Use good quality chocolate and peanut butter for the best flavor.
- Line your baking pan with parchment paper for easy removal and clean-up.
- Be sure to fully cover the Reese’s Cups with the brownie batter to ensure they melt into the brownies.
- Let the brownies cool completely before frosting to avoid a melty mess.
- Have fun with it! This recipe is all about indulgence, so don’t be afraid to add your favorite toppings.
Nutrition
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