Why You’ll Love This Recipe

Incredibly fudgy with rich chocolate flavor and soft marshmallow swirls.
Sweet and indulgent—perfect served with milk or vanilla ice cream.
Easy to make with simple ingredients.

Marshmallow Brownies

Ingredients

White granulated sugar
Large eggs
Egg yolk
Unsalted butter, melted
Pure vanilla extract
Oil (canola or vegetable)
All‑purpose flour
Unsweetened (Dutch process) cocoa powder
Cornstarch
Salt
Semi‑sweet chocolate chips
Marshmallow creme (fluff)

Directions

Preheat oven to 325°F. Spray a 9×9‑inch pan with nonstick spray, line bottom and two sides with parchment, and spray again.
In a medium bowl, sift together flour, cocoa powder, cornstarch, and salt. Set aside.
In a mixer bowl, beat sugar, eggs, and egg yolk on high speed for 5 minutes until pale. Melt butter, let cool, then mix in oil and vanilla on low.
Add dry ingredients and mix on low until just combined. Fold in chocolate chips.
Pour batter into prepared pan. Melt marshmallow fluff briefly, then dollop by teaspoonfuls on top. Swirl lightly with a knife.
Bake for 45–55 minutes. The brownies are done when a toothpick inserted has slight moisture.
Cool completely before cutting.

Servings and Timing

Servings: 16 brownies.
Prep time: 15 minutes.
Cook time: 50 minutes.
Total time: ~1 hour 5 minutes.

Variations

Use an 8×8‑inch pan for thicker brownies, or double the recipe for a 9×13‑inch pan.
Try broiling the marshmallow swirl on top to create a toasted, toffee‑like finish.

Storage/Reheating

Room temperature: Store in an airtight container for up to 5 days.
Freezing: Freeze individual squares in an airtight container for up to 30 days.
Reheat: Warm in the microwave until gooey, especially delicious with a scoop of vanilla ice cream.

FAQs

1. What makes these brownies so fudgy?

These brownies achieve fudgy richness thanks to a high sugar‑and‑fat ratio, plus the addition of marshmallow fluff that adds extra moisture and softness.

2. Can I use regular marshmallows instead of marshmallow fluff?

Yes—just melt them and swirl gently into the batter, though you may get slightly different texture.

3. Will the brownies sink in the middle?

If underbaked, they may sink; bake until a toothpick shows slight moisture to avoid this.

4. Can I use gluten‑free flour?

Yes—many readers have substituted King Arthur’s gluten‑free 1:1 flour with success.

5. How do I get clean brownie cuts?

Use a sharp knife wiped clean between cuts, or chill the brownies before slicing.

6. What if I don’t have parchment paper?

You can spray the pan generously, but parchment makes removal much easier.

7. Can I reduce sugar?

You can reduce sugar slightly, but it may affect texture—keep in mind mar‑style indulgence.

8. Can I make this with a brownie mix?

Instead of from‑scratch batter, you can swirl marshmallow fluff into a boxed brownie mix for a quick version.

9. Why swirl instead of mixing in?

Swirling gives gooey marshmallow pockets and a visual contrast without overwhelming the batter.

10. Are these good warm or cooled?

While these are great any way you serve them, many love them warmed—especially with ice cream—for maximum gooey comfort.

Conclusion

These marshmallow brownies are a chocolate lover’s dream—with fudgy brownie, gooey marshmallow swirls, and melted chocolate chips all in one. Easy to customize and decadently satisfying, they’re perfect for sharing…or keeping all to yourself.

Marshmallow Brownies

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Ultra-fudgy chocolate brownies with swirls of marshmallow fluff and gooey chocolate chips—perfectly indulgent without needing graham crackers.

Total Time: 1 hour 5 minutes
Yield: 16 brownies

Ingredients

1 1/4 cups white granulated sugar

2 large eggs

1 large egg yolk

1/2 cup unsalted butter, melted

1 tsp pure vanilla extract

1/4 cup oil (canola or vegetable)

3/4 cup all-purpose flour

1/2 cup unsweetened (Dutch process) cocoa powder

1 tbsp cornstarch

1/2 tsp salt

1 cup semi-sweet chocolate chips

1 cup marshmallow creme (fluff)

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Instructions

Preheat oven to 325°F. Spray a 9×9-inch baking pan with nonstick spray, line the bottom and two sides with parchment paper, and spray again.
In a medium bowl, sift together flour, cocoa powder, cornstarch, and salt. Set aside.
In a mixer bowl, beat sugar, eggs, and egg yolk on high speed for 5 minutes until pale and thick.
Melt the butter and let it cool slightly. Mix in the oil and vanilla on low speed until combined.
Add the dry ingredients to the wet ingredients and mix on low until just combined.
Fold in the chocolate chips.
Pour the batter into the prepared pan. Briefly warm the marshmallow fluff in the microwave until slightly loosened, then dollop teaspoonfuls over the top of the batter. Swirl gently with a knife.
Bake for 45–55 minutes, or until a toothpick inserted in the center comes out with slight moisture.
Cool completely in the pan before cutting into squares.

Notes

For thicker brownies, use an 8×8-inch pan and increase baking time slightly.
Double the recipe for a 9×13-inch pan.
Broil the marshmallow topping briefly for a toasted effect.
Store at room temperature in an airtight container for up to 5 days, or freeze for up to 30 days.
For clean cuts, chill the brownies before slicing and wipe the knife between cuts.

Author: Julia
Prep Time: 15 minutes
Cook Time: 50 minutes
Category: Dessert
Method: Baking
Cuisine: American
Diet: Vegetarian