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Chocolate and peanut butter are pretty much the ultimate combo, and these brownies prove it. They’re my go-to when I want something rich, fudgy, and super easy to throw together. No fancy steps, no endless mixing—just a box of brownie mix, a little peanut butter, and a few basic ingredients. And the best part? You get to control the peanut butter swirl. Some days, I keep it light, but when I’m feeling extra, I go all in with an extra spoonful or two.

Stack of chocolate peanut butter brownies next to more brownies. Glob of peanut butter on top.

I’ve made these brownies so many times, and they never last long. The edges get perfectly chewy, the center stays nice and soft, and that peanut butter drizzle just takes them over the top. They’re the kind of treat that makes you want to grab a cold glass of milk.

Ingredients You Will Need

Ingredients for chocolate peanut butter brownies on white background.

Brownie Mix: is the base of the recipe, providing all the dry ingredients like flour, sugar, and cocoa powder. It’s a shortcut that still gives you a delicious brownie without having to measure out individual dry ingredients.
Peanut butter: adds flavor to the brownies. The peanut butter swirled into the batter gives a creamy texture and a tasty peanut butter contrast to the chocolate flavor.
Egg: helps bind the ingredients together and gives the brownies structure and moisture. It also contributes to the soft, chewy texture.
Water hydrates the dry ingredients, helping everything mix together and form the right consistency. It also helps create a smooth texture.
Vegetable oil: adds moisture to the brownies, making them extra fudgy and soft. It also helps them bake up with the right texture—chewy without being dry.

Frequently Asked Questions

How do I know when the brownies are done? Check for doneness by inserting a toothpick into the center. If it comes out clean or with just a few crumbs, they’re ready. If there’s batter sticking to it, give them a few more minutes in the oven.

Why do my brownies feel too soft or undercooked? If your brownies are too soft, it might be because they need a little more time in the oven. Every oven is different, so the first time you make them, check them a few minutes before the suggested bake time to see how they’re doing.

Why do my brownies have a hard crust on top? A hard crust can sometimes form on top of brownies if they’ve been baked a little too long or at too high a temperature. Try baking them at a lower temperature and watch the time closely. It could also be the oil or peanut butter affecting the texture.

Why are my brownies too gooey in the center? If the center is too gooey, it might be because they haven’t baked long enough. Check them at the lower end of the baking time, and if a toothpick inserted into the center comes out wet, give them a few more minutes in the oven. If the edges are done but the center is still gooey, try covering the pan with foil to prevent the edges from overbaking while the center finishes cooking.

Can I use creamy or crunchy peanut butter? You can use either creamy or crunchy peanut butter! If you want a smooth, velvety texture, go with creamy. If you prefer some extra crunch, then crunchy peanut butter adds a nice little texture to the brownies. It’s all about your preference!

Pouring water into brown powder. — Add the water to the brownie mix.

Egg white and yolk in brown powder with whisk. — Add the egg and combine with a whisk.

Helpful Tips

Don’t overmix the batter: When mixing your brownie batter, stop as soon as everything is blended. Overmixing can lead to denser brownies, and you want them to stay light and fudgy. Just mix until smooth!

Use room temperature peanut butter: If your peanut butter is too cold or hard, it might not drizzle easily over the batter. Let it sit at room temperature for a few minutes before drizzling, or microwave it for 10-15 seconds to soften it up.

Use a toothpick to check for doneness: The best way to tell when your brownies are done is to insert a toothpick into the center. If it comes out clean or with a few crumbs, they’re done! If there’s wet batter, they need a few more minutes in the oven.

Cool completely before cutting: After baking, let the brownies cool completely before cutting them into squares. This ensures they firm up and cut more cleanly. If you try to cut them while they’re still warm, they might fall apart.

Don’t overbake: Brownies continue to cook slightly once removed from the oven, so it’s better to slightly underbake them than overbake them. They should still look a little soft in the center when you pull them out—this ensures they’re fudgy.

Whisk in brown batter with brown powder on edges. — Combine all ingredients with a whisk.

Whisk with brown batter above bowl of brown batter. — Combine just until mixed. Don’t overmix.

How to Store

Store at room temperature (up to 3-4 days): Keep your brownies in an airtight container at room temperature for up to 3-4 days. This will help them stay moist and fresh. Make sure the container is sealed well to prevent them from drying out.

Refrigerate for longer freshness (up to 1 week): If you want your brownies to last a bit longer, store them in the fridge. Place them in an airtight container or wrap them tightly in plastic wrap to keep them from absorbing other smells in the fridge. They’ll stay fresh for up to a week.

Freeze for extended storage (up to 3 months): To extend the shelf life, freeze your brownies. Wrap individual brownies in plastic wrap or aluminum foil, and then place them in a freezer-safe bag or airtight container. When you’re ready to enjoy them, let them thaw at room temperature for a few hours, or heat them in the microwave for a warm treat.

Keep layers separated: If you’re storing more than one layer of brownies in the container, place a layer of parchment paper or wax paper between the layers to prevent them from sticking together. This also makes it easier to remove individual brownies when you want them.

Brown batter being poured into baking pan. — Pour batter into 8″x8″ pan.

Brownie batter with peanut butter swirls. — Swirl in peanut butter.

Substitutions and Variations

Peanut Butter: Swap it with almond butter, cashew butter, or even Nutella for a different flavor.

Vegetable Oil: Use melted butter or coconut oil for a richer taste.

Egg: If you’re out of eggs, use ¼ cup unsweetened applesauce or mashed banana for a slightly different texture. A flax egg (1 tbsp ground flaxseed + 3 tbsp water) also works.

Chocolate Peanut Butter Cup Brownies: Chop up peanut butter cups and fold them into the batter for an extra indulgent treat.

Double Chocolate Peanut Butter Brownies: Stir in a handful of chocolate chips into the batter before baking.

Oreo Peanut Butter Brownies: Crush some Oreos and mix them into the batter, or place whole Oreos at the bottom of the pan before pouring in the batter.

Nine chocolate peanut butter brownies on parchment paper.

Chocolate peanut butter brownies next to knife and spoon of peanut butter.

What to Serve with Chocolate Peanut Butter Brownies

Vanilla Ice Cream: A warm brownie with a scoop of vanilla ice cream is always a delicious treat.

Pretzels: Serve alongside for a salty, crunchy contrast.

Coffee or Espresso: The bitterness of coffee complements the sweetness of the brownies.

Brownie Trifle: Layer crumbled brownies with whipped cream and pudding in a glass for a fancy dessert.

Close up of two chocolate peanut butter brownies with more in the background.

Stack of six chocolate peanut butter brownies.

Other Recipes You May Enjoy

If you like Chocolate Peanut Butter Brownies, you might also like my No-Bake Brownies or my Old-Fashioned Peanut Butter Cookies. These Chocolate Peanut Butter Lava Cakes and this Chocolate Ischler are also delicious.

Final Thoughts

These chocolate peanut butter brownies never last long in my house; every time I make them, someone’s stealing a piece before they’ve even cooled! I love sneaking a warm one straight from the pan, but they’re just as good with a scoop of ice cream (or, let’s be honest, for breakfast the next day). If you’re anything like me, you’ll be making these on repeat!