Recipe

Peanut Butter Brownies

Ultra fudgy brownies with a crackly top, crisp edges, and thick peanut butter swirls in every bite.

By Matt Campbell

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4.8

A pan of fudgy peanut butter swirl brownies cut into squares on a parchment lined baking pan on a warm kitchen counter

If you have ever stood in your kitchen holding a jar of peanut butter and a box of cocoa like, “I can make this work,” welcome. These peanut butter brownies are my favorite kind of chaotic good: deeply chocolatey, shiny and crackly on top, and swirled with big ribbons of peanut butter that stay creamy after baking.

No mixer. No fancy chocolate bars. Just accessible ingredients, clear steps, and a couple little moves that make them taste like you tried harder than you did. You will get crisp edges, a fudgy center, and that sweet salty peanut butter moment that makes you pause mid-bite.

Measured brownie ingredients including cocoa powder, flour, sugar, eggs, butter, and peanut butter arranged on a tidy kitchen counter

Why It Works

Fudgy texture, not cakey: A cocoa based batter with the right flour ratio keeps the center dense and rich.
Crackly top: Whisking the warm butter with sugar helps dissolve it slightly, which can encourage that classic shiny brownie crust.
Real peanut butter swirls: Warming the peanut butter makes it swirl instead of clumping, so you get ribbons through the whole pan.
Low drama: One bowl, one pan, and a forgiving bake time window so you can pull them when they are just set.

Pairs Well With

Storage Tips

Room temperature: Store tightly covered for up to 3 days. Brownies stay fudgiest when you keep air out.

Refrigerator: Up to 1 week in an airtight container. Let a square sit at room temp for 10 minutes before eating for the best texture.

Freezer: Freeze squares up to 2 months. Wrap individually in plastic wrap, then stash in a freezer bag. Thaw overnight in the fridge or for about 30 to 60 minutes at room temp.

Pro tip: If you like a warm, gooey bite, microwave a square for 8 to 12 seconds. The peanut butter turns extra silky.

Common Questions

Can I use natural peanut butter?

Yes, but stir it extremely well first. Natural peanut butter can be oily or dry depending on the jar. If it is very runny, the swirl can melt into the batter. If it is very stiff, warm it a little longer so it loosens up.

How do I know when brownies are done?

Look for set edges and a center that no longer looks wet. A toothpick should come out with moist crumbs, not clean. Overbaking is the fastest way to lose fudginess.

Can I make these in a 9x13 pan?

Yes, with a small scaling note. A 9x13 pan is a bit less than double the area of an 8x8, so you have options. For a similar thickness, make about 1 3/4 batches (easy approach: make 2 batches and hold back a small scoop of batter). If you double the recipe, your brownies will be thicker and will likely need a longer bake. Start checking at 28 minutes, but do not be surprised if it takes closer to 35 to 45 minutes depending on your pan.

Can I add chocolate chips or nuts?

Absolutely. Add up to 3/4 cup semisweet chips or chopped peanuts. If you add both, keep each to about 1/2 cup so the brownies still slice cleanly.

Why did my peanut butter sink?

Usually the peanut butter was too warm or too thin, or the batter was overmixed and loosened up. Warm it just until it is pourable, then swirl gently and bake right away.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

8x8 inch metal baking pan
Parchment paper (recommended for easy lifting)
Mixing bowl
Whisk
Rubber spatula
Measuring cups and spoons
Butter knife or skewer for swirling
Wire rack for cooling

I started making peanut butter brownies when I was in my “I want dessert but I do not want a sink full of dishes” era, which is basically always. Peanut butter is the ultimate shortcut ingredient. It adds richness, salt, and that nostalgic candy bar vibe without needing frosting or anything fancy. I love bringing these to casual get-togethers because they look impressive, but the process is just whisk, pour, swirl, bake. It feels like kitchen magic you can do on a Tuesday.