Soft and Chewy Peanut Butter Sugar Brownies are my kind of weeknight baking project: fudgy cocoa brownies with a simple peanut butter sugar swirl that looks special but doesn’t take much effort.
The brownie base bakes up soft and chewy, with that deep cocoa flavor I always want in a homemade brownie. The swirl is sweet, a little salty, and very “peanut butter cup” in spirit, even though it’s just a quick mix you stir together.
I like these for cookie trays, potlucks, and anytime I need a 16-piece pan dessert that slices clean and holds up well. They’re also great with coffee, and I think they’re even better after a short chill.
Why You’ll Love This Recipe
Soft and Chewy: These bake up with set edges and a tender center, so you get that brownie chew without dry corners.
Big Chocolate Flavor: Cocoa powder does the heavy lifting here, so the brownies taste rich and chocolatey without needing fancy ingredients.
Peanut Butter Swirl: The swirl is sweet and a little salty, and it stays soft instead of baking into a hard layer.
One Pan Dessert: An 8-inch pan is the perfect size for a thick brownie, and you get neat little squares that are easy to serve.
Easy to Tweak: Chocolate chips, peanut butter chips, or chopped peanuts all work, depending on what you want in the bite.
Ingredients You’ll Need
Brownie Batter
- Unsalted butter: Melted butter keeps this simple and gives the brownies that fudgy texture. I like unsalted so I can control the salt level.
- Granulated sugar: This gives the crackly top and helps the brownies stay chewy.
- Light brown sugar: The molasses note makes the chocolate taste deeper, and it keeps the middle softer. Dark brown sugar works too.
- Eggs: Room temp eggs mix in smoother and help the batter thicken up the way it should.
- Vanilla extract: Don’t skip it. It makes cocoa brownies taste more finished.
- Unsweetened cocoa powder: This is the main chocolate flavor, so use one you like the taste of. Natural or Dutch-process both work here.
- All-purpose flour: I use regular flour here, and I’m careful not to overmix once it goes in.
- Fine salt: A little salt makes both the chocolate and peanut butter taste better.
- Baking powder: Just enough lift so they aren’t dense like fudge, but still stay thick and chewy.
- Semisweet chocolate chips (optional): I like these for little pockets of chocolate, but the brownies are still great without them. Milk chocolate chips are fine if that’s what you have.
Peanut Butter Sugar Swirl
- Creamy peanut butter: Regular creamy peanut butter is the smoothest and easiest for swirling. Natural peanut butter can work, but it needs extra mixing and sometimes a touch more sugar.
- Granulated sugar: This makes the swirl taste like peanut butter “frosting,” but it still bakes right into the top.
- Unsalted butter: Melted butter loosens the swirl so it’s easy to dollop and drag through the batter.
- Milk: Just enough to make the peanut butter mixture pourable. Any milk you have is fine.
- Salt: A pinch keeps the swirl from tasting flat, especially if your peanut butter is on the sweet side.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F and set a rack in the middle. Line an 8-inch square pan with parchment paper, leaving an overhang, then lightly grease it.
- Mix the sugars: In a bowl, whisk the melted butter, granulated sugar, and brown sugar until the mixture looks glossy.
- Add the eggs: Whisk in the eggs and vanilla until smooth and slightly thickened.
- Add the cocoa: Whisk in the cocoa powder, salt, and baking powder until fully combined and no dry cocoa pockets remain.
- Add the flour: Fold in the flour just until you don’t see dry streaks. Fold in the chocolate chips if you’re using them.
- Spread the batter: Scrape the brownie batter into the prepared pan and spread it into an even layer.
- Mix the swirl: Stir the peanut butter, sugar, melted butter, milk, and a pinch of salt until smooth and pourable.
- Swirl: Dollop the peanut butter mixture over the brownie batter, then gently swirl with a knife. Keep the swirls loose and don’t overmix.
- Bake: Bake for 28 to 32 minutes, until the edges are set and a tester in the center comes out with a few moist crumbs.
- Cool and slice: Cool completely in the pan, then lift out using the parchment overhang and slice into squares.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Use regular creamy peanut butter. The classic jarred kind swirls the easiest and stays smooth. If you’re using natural peanut butter, mix it really well first and add a little extra sugar if it tastes too “plain.”
Don’t overmix after the flour goes in. Fold just until the flour disappears. Overmixing can make the brownies more cakey and less chewy.
Pull them when the center looks a little underdone. For softer brownies, I take them out when the center still looks slightly glossy and a tester shows a few moist crumbs. They finish setting as they cool.
Go easy on the swirl. A few big figure-eights with a knife is plenty. If you keep swirling, the peanut butter just blends into the batter and you lose the pretty streaks.
Chill before slicing if you want clean cuts. Even 30 minutes in the fridge helps a lot. Use a sharp knife and wipe it between cuts if needed.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Milk: A cold glass of milk is classic with peanut butter brownies. It’s especially nice if you cut them a little smaller since they’re rich.
- Coffee: These are really good with coffee, hot or iced. I usually go with something simple like drip coffee or a latte.
- Ice cream: If you want dessert-dessert, serve a brownie square with vanilla ice cream. Let the brownie sit at room temp for a few minutes first so it’s softer.
- Fruit: Strawberries or raspberries on the side are an easy way to lighten up the plate. The tart fruit is a good contrast with the sweet swirl.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store brownies covered at room temperature for 2 to 3 days. I keep them right in the pan with foil over the top, or in a container with a tight lid so they don’t dry out.
For a slightly firmer, cleaner slice, store leftovers covered in the fridge for up to 4 days. Let a square sit out for a bit before eating, or warm it for a few seconds in the microwave if you like them softer.
If you want them to last longer, freeze individual portions in an airtight container or freezer bag. Thaw in the fridge overnight or on the counter for about an hour.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I use natural peanut butter for the swirl?
You can, but it takes a little extra effort. Mix the jar really well so it isn’t oily, and I’d add 1 to 2 teaspoons of extra sugar if it tastes less sweet than regular creamy peanut butter.
How do I know when these brownies are done?
I look for set edges and a center that’s just a little underdone. A toothpick in the middle should come out with a few moist crumbs (not wet batter), and the center may still look slightly glossy.
Can I make these in a 9-inch pan?
Yes, but they’ll be thinner and they’ll bake faster. Start checking around 22 to 26 minutes, and pull them when the center still looks a little soft.
Do I have to use chocolate chips?
No. The brownies have plenty of chocolate flavor from the cocoa powder. If you want a change, peanut butter chips or chopped peanuts are great in this batter.
Why did my swirl sink or disappear?
This usually happens if the peanut butter mixture is too thick or you swirl too much. Make sure it’s smooth and pourable, then do just a few gentle passes with the knife.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Soft and Chewy Peanut Butter Sugar Brownies
INGREDIENTS
Brownie Batter
- 1/2 cup unsalted butter melted
- 1 cup granulated sugar
- 1/2 cup light brown sugar packed
- 2 large eggs room temperature
- 2 tsp vanilla extract
- 3/4 cup unsweetened cocoa powder
- 3/4 cup all purpose flour
- 1/2 tsp fine salt
- 1/2 tsp baking powder
- 1/2 cup semisweet chocolate chips optional.
Peanut Butter Sugar Swirl
- 1/2 cup creamy peanut butter
- 3 tbsp granulated sugar
- 1 tbsp unsalted butter melted
- 1 tbsp milk
- pinch of salt.
INSTRUCTIONS
Pan and Oven
- preheat oven to 350 F and set rack in the middle
- line an 8 inch square pan with parchment paper leaving overhang and lightly grease.
Brownie Batter
- whisk melted butter granulated sugar and brown sugar until glossy
- whisk in eggs and vanilla until smooth and slightly thickened
- whisk in cocoa powder salt and baking powder until fully combined
- fold in flour just until no dry streaks remain then fold in chocolate chips if using
- spread batter evenly in prepared pan.
Peanut Butter Swirl and Bake
- stir peanut butter sugar melted butter milk and a pinch of salt until smooth and pourable
- dollop peanut butter mixture over the brownie batter and gently swirl with a knife without overmixing
- bake until edges are set and center is slightly underdone with a few moist crumbs on a tester 28 to 32 minutes
- cool completely in pan then lift out and slice.
