If a brownie and a peanut butter cup had a power couple moment, this would be their blockbuster. Thick, glossy, melt-in-your-mouth squares with a salty-sweet swirl that looks fancy and tastes like a cheat code.

No mixers, no drama, no “please rise correctly” prayers—just bold flavor and ridiculous texture.

You’ll pull these out of the oven and become that friend: the one everyone “casually” visits around 8 p.m.

Should you gatekeep? Possibly.

Will you? Not a chance.

Why This Recipe Never Fails

This recipe stacks the deck in your favor with high-fat cocoa, melted chocolate, and a touch of oil for guaranteed fudge.

Brown sugar adds moisture and chew, so even if you overbake a minute (hey, it happens), you still win. The peanut butter cup swirl isn’t just pretty—its fat content keeps the top glossy and tender.

Stir by hand, bake once, feel like a pastry wizard.

Fudgy Brownies with Peanut Butter Cup Swirl: Irresistible, Fast, Legendary

Recipe by Wendy CarterCourse: Dessert

Servings

servings

Prep time

minutes

Cooking time

minutes

Calories

285

kcal

Ingredients

1/2 cup (115 g) unsalted butter, plus extra for the pan
2 oz (55 g) semisweet chocolate, chopped or chips
1/4 cup (60 ml) neutral oil (canola or light olive)
1 cup (200 g) granulated sugar
1/2 cup (100 g) packed brown sugar
2 large eggs + 1 large egg yolk, room temperature
2 tsp vanilla extract
3/4 cup (90 g) all-purpose flour
1/2 cup (50 g) Dutch-process cocoa powder (natural works, but Dutch = richer)
1/2 tsp fine sea salt
1/2 tsp instant espresso powder (optional, boosts chocolate)
1/2 cup (85 g) mini chocolate chips (optional mix-in)
3/4 cup (180 g) creamy peanut butter, warmed slightly
1 to 1 1/2 cups peanut butter cups, chopped (mini or regular)
Flaky salt, for finish (optional, highly recommended)

Step-by-Step Instructions

Prep the pan: Line an 8-inch square pan with a parchment sling, leaving overhang for easy lift. Lightly butter or spray. Preheat oven to 350ºF (175ºC).
Melt butter + chocolate: In a medium saucepan over low heat, melt butter and semisweet chocolate, stirring until smooth. Remove from heat and whisk in the oil.
Whisk in sugars: Add granulated and brown sugar to the warm mixture and whisk until glossy. It’ll look thick—good.
Add eggs + vanilla: Whisk in eggs and yolk one at a time, then vanilla, until the batter turns shiny and a bit elastic. This gives that classic crinkle top.
Dry ingredients in: Sift flour, cocoa, salt, and espresso powder right into the pot. Fold with a spatula until just combined. Do not overmix. Stir in chocolate chips if using.
Spread and swirl: Scrape batter into the pan and smooth. Warm the peanut butter in the microwave for 15–20 seconds until pourable. Dollop over the batter in 6–8 spoonfuls. Use a butter knife to gently swirl in figure-eights—don’t overwork or you’ll lose the marbling.
Top with peanut butter cups: Scatter chopped cups evenly and press lightly so they nestle but don’t sink.
Bake: Bake 28–34 minutes, until edges are set and a toothpick inserted 2 inches from the edge comes out with a few moist crumbs (center may look slightly soft).
Finish + cool: Sprinkle flaky salt. Cool in pan on a rack at least 1 hour, then lift out and slice with a warm knife. Yes, waiting is painful. Yes, it’s worth it.

Smart Storage Guide

Room temp: Airtight container, up to 3 days. Place a piece of parchment between layers to protect the swirl.
Fridge: Up to 1 week; texture becomes ultra-fudgy.
Bring to room temp for best flavor.
Freeze: Wrap individual squares tightly, then bag. Freeze up to 2 months.
Thaw at room temp 1–2 hours or microwave in short bursts.

Why This is Good for You

No, it’s not a kale salad. But it’s a morale booster with portion control baked in.

Peanut butter brings protein and healthy fats that keep these from being a sugar rocket. Cocoa offers polyphenols and that happiness hit we all need on a Tuesday.

And making dessert at home means clean ingredients, predictable portions, and fewer weird additives—FYI, that counts.

Nutrition Stats

Per brownie (1/16 pan): ~285 calories
Fat: ~16 g (6 g sat)
Carbohydrates: ~33 g
Sugars: ~24 g
Protein: ~5 g
Fiber: ~2 g
Sodium: ~140 mg

Note: Estimates vary based on brand, PB cups used, and optional mix-ins.

Don’t Make These Errors

Overbaking: Pull them when the edges set and the center wobbles slightly. Dry brownies are a crime.
Cold eggs: Room-temp eggs emulsify better, giving you that shiny, crackly top.
Overmixing after flour goes in: You’ll activate gluten and lose fudginess.
Fold gently.
Thick peanut butter: If it’s stiff, it’ll clump instead of swirl. Warm it 15–20 seconds.
Wrong pan size: A 9-inch pan bakes faster/thinner.
If you use it, start checking at 22 minutes.

Different Ways to Make This

Gluten-free: Swap in a 1:1 gluten-free flour blend with xanthan gum. Keep an eye on bake time—often 2–3 minutes less.
Dairy-free: Use vegan butter and dairy-free chocolate.
Choose a natural peanut butter that’s smooth when warmed.
Nut-free vibe: Use sunflower seed butter and chopped sunflower “cups” or omit cups and swirl in cookie butter.
Espresso lovers: Double the espresso powder and add a tablespoon of brewed coffee (reduce oil by 1 tablespoon).
Salted pretzel crunch: Fold in 1 cup crushed pretzels and sprinkle some on top before baking. Sweet-salty-crunchy = win.
Double peanut: Add 1/2 cup peanut butter chips to the batter for more PB punch.

FAQ

Can I use natural peanut butter?

Yes, but make sure it’s well-stirred and slightly warmed so it’s pourable.

If it’s too oily or too stiff, the swirl won’t integrate well, and you might get greasy pockets or clumps.

How do I get the shiny, crackly top?

Whisk the sugars into the warm butter-chocolate mix, then whisk eggs until the batter is glossy and cohesive. That sugar-egg emulsion creates the signature crust.

Don’t skip room-temp eggs.

What if I only have cocoa and no chocolate?

Add an extra 2 tablespoons oil and increase cocoa to 3/4 cup plus 2 tablespoons. Flavor will skew slightly more “cocoa brownie,” but still fudgy and rich, IMO.

Can I double the recipe?

Absolutely.

Use a 9×13-inch pan and bake 30–36 minutes. Check early—ovens vary.

Let cool longer; bigger slabs retain heat.

How do I know they’re done?

Edges set, center slightly soft, and a toothpick near the edge hits moist crumbs (not wet batter). If the middle shakes like pudding, give it 2–3 more minutes.

Do I have to add peanut butter cups?

Nope.

The swirl alone is fantastic. Or sub chopped dark chocolate, toffee bits, or pretzels for texture and contrast.

End Notes

These Fudgy Brownies with Peanut Butter Cup Swirl deliver bakery drama with weeknight effort.

The batter is simple, the swirl’s photogenic, and the texture hits that sweet spot between gooey and structured. Make them once and you’ll memorize the steps without trying—dangerous, in the best way.

Share generously… or stash a corner piece for tomorrow. Your call.

Fudgy Brownies with Peanut Butter Cup Swirl: Irresistible, Fast, Legendary

Why This Recipe Never Fails