Dark Chocolate Peanut Butter Swirl Blondies – Gooey, Fudgy, and Totally Irresistible

These blondies are everything you want in a dessert: chewy edges, a soft center, and rich swirls of peanut butter melting into pockets of dark chocolate. They come together with pantry staples and bake up in under 30 minutes. If you’re in the mood for something comforting but not too fussy, this is your go-to bar.

They slice cleanly, pack well, and taste even better the next day. Keep this recipe in your back pocket for bake sales, casual dinners, or a late-night bake.

Print Recipe

Dark Chocolate Peanut Butter Swirl Blondies - Gooey, Fudgy, and Totally Irresistible

Prep Time15 minutes mins

Cook Time30 minutes mins

Total Time45 minutes mins

Servings: 12 servings

Ingredients

• 1/2 cup (115 g) unsalted butter, melted and slightly cooled
• 1 cup (200 g) packed light brown sugar
• 1 large egg, room temperature
• 2 teaspoons vanilla extract
• 1 cup (125 g) all-purpose flour
• 1/2 teaspoon baking powder
• 1/4 teaspoon fine salt
• 1/2 cup (90 g) dark chocolate chips or chunks (60–70% cacao)
• 1/3 cup (85 g) creamy peanut butter, slightly warmed for swirling
• Optional: 1–2 tablespoons milk or semisweet chips for extra chocolate pockets
• Optional finish: flaky sea salt for sprinkling

Instructions

• Prep the pan: Heat oven to 350°F (175°C). Line an 8-inch square pan with parchment, leaving overhang for easy lifting.Lightly grease.
• Mix the wet ingredients: In a medium bowl, whisk melted butter and brown sugar until glossy. Add egg and vanilla. Whisk until the mixture looks thick and cohesive.
• Add the dry ingredients: Sprinkle flour, baking powder, and salt over the bowl.Fold gently with a spatula until just combined. Do not overmix.
• Stir in chocolate: Fold in dark chocolate chips or chunks. The batter will be thick.
• Spread the batter: Scrape into the prepared pan and smooth the top.
• Swirl the peanut butter: Warm the peanut butter for 10–15 seconds in the microwave until loosened.Dollop over the batter in 6–8 spoonfuls. Drag a knife or skewer through in gentle figure-eights to create swirls. Don’t overdo it.
• Bake: Bake 18–24 minutes, until the edges are set and golden and the center looks just set with a slight jiggle.A toothpick should come out with a few moist crumbs, not wet batter.
• Finish and cool: If using, sprinkle with flaky sea salt. Cool in the pan for at least 30 minutes before lifting out and slicing into 9–16 squares.

What Makes This Recipe So Good

• Perfect texture: Buttery, chewy, and slightly fudgy with crisp edges.
• Sweet-salty balance: Dark chocolate keeps the bars from being too sweet, while peanut butter adds a savory, nutty swirl.
• One-bowl batter: Minimal dishes and simple steps make this weeknight-friendly.
• Flexible: Works with creamy or natural peanut butter and different chocolate percentages.
• Reliable bake: Clear cues help you avoid dry or underbaked bars.

Ingredients

• 1/2 cup (115 g) unsalted butter, melted and slightly cooled
• 1 cup (200 g) packed light brown sugar
• 1 large egg, room temperature
• 2 teaspoons vanilla extract
• 1 cup (125 g) all-purpose flour
• 1/2 teaspoon baking powder
• 1/4 teaspoon fine salt
• 1/2 cup (90 g) dark chocolate chips or chunks (60–70% cacao)
• 1/3 cup (85 g) creamy peanut butter, slightly warmed for swirling
• Optional: 1–2 tablespoons milk or semisweet chips for extra chocolate pockets
• Optional finish: flaky sea salt for sprinkling

How to Make It

1. Prep the pan: Heat oven to 350°F (175°C). Line an 8-inch square pan with parchment, leaving overhang for easy lifting.

   Lightly grease.

2. Mix the wet ingredients: In a medium bowl, whisk melted butter and brown sugar until glossy. Add egg and vanilla. Whisk until the mixture looks thick and cohesive.
3. Add the dry ingredients: Sprinkle flour, baking powder, and salt over the bowl.

   Fold gently with a spatula until just combined. Do not overmix.

4. Stir in chocolate: Fold in dark chocolate chips or chunks. The batter will be thick.
5. Spread the batter: Scrape into the prepared pan and smooth the top.
6. Swirl the peanut butter: Warm the peanut butter for 10–15 seconds in the microwave until loosened.

   Dollop over the batter in 6–8 spoonfuls. Drag a knife or skewer through in gentle figure-eights to create swirls. Don’t overdo it.

7. Bake: Bake 18–24 minutes, until the edges are set and golden and the center looks just set with a slight jiggle.

   A toothpick should come out with a few moist crumbs, not wet batter.

8. Finish and cool: If using, sprinkle with flaky sea salt. Cool in the pan for at least 30 minutes before lifting out and slicing into 9–16 squares.

How to Store

• Room temperature: Store in an airtight container for 3–4 days. Layer with parchment to prevent sticking.
• Refrigerator: Keeps for up to 1 week.

  The texture becomes fudgier when chilled.

• Freezer: Wrap bars individually and freeze up to 2 months. Thaw at room temp or warm for 10–15 seconds in the microwave.

Why This is Good for You

• Dark chocolate: Offers antioxidants and a deeper cocoa flavor, so you can use less sugar overall.
• Peanut butter: Adds protein and healthy fats that help with satiety.
• Balanced indulgence: These blondies satisfy a sweet craving without being cloying, thanks to the bittersweet chocolate and a touch of salt.

Pitfalls to Watch Out For

• Overbaking: Pull them when the center is just set. Overbaked blondies turn cakey and dry.
• Overmixing: Stir only until the flour disappears to keep the crumb tender.
• Too-stiff peanut butter: If it’s thick, the swirl will clump.

  Warm it briefly to pourable consistency.

• Hot butter scramble: Let melted butter cool a bit before adding the egg to avoid curdling.
• Wrong pan size: A larger pan yields thin, overbaked bars. Stick to an 8-inch square for the best thickness.

Recipe Variations

• Gluten-free: Use a 1:1 gluten-free flour blend with xanthan gum. Check bake early.
• Almond twist: Swap peanut butter for almond butter and add 1/4 teaspoon almond extract.
• Espresso boost: Mix 1 teaspoon instant espresso into the butter-sugar mixture for deeper chocolate notes.
• Peanut crunch: Sprinkle 1/4 cup chopped roasted peanuts on top before baking.
• Extra gooey: Add 2 tablespoons peanut butter chips or milk chocolate chips for more melty bits.
• Dairy-free: Use plant-based butter and dairy-free chocolate.

FAQ

Can I use natural peanut butter?

Yes.

Stir well to reincorporate the oil, then warm slightly so it loosens. Natural peanut butter makes a slightly less sweet, more pronounced peanut flavor.

Can I double the recipe?

Yes. Bake in a 9×13-inch pan for 22–28 minutes.

Check early; edges should be set and the center just cooked.

Do I need a mixer?

No. A whisk and spatula are enough. The batter comes together easily by hand.

What if I only have semisweet chocolate?

Use it.

Reduce the brown sugar by 1–2 tablespoons if you prefer less sweetness, or keep as is for a classic blondie vibe.

How do I get clean slices?

Cool completely, then use a sharp knife. Wipe the blade between cuts for neat edges.

Can I make them nut-free?

Yes. Skip the peanut butter and swirl in tahini or sunflower seed butter.

Taste and add a pinch of extra salt to balance.

Final Thoughts

These Dark Chocolate Peanut Butter Swirl Blondies are the kind of treat that feels special without demanding much from you. A few bowls, a quick swirl, and you’re set. They’re cozy, crowd-pleasing, and endlessly adaptable.

Keep a batch on hand for an easy dessert win any day of the week.