Decadent Reese’s Marshmallow Brownies are a warm, gooey treat that mixes rich chocolate with peanut butter cups and soft marshmallows. Try this when you want a simple crowd-pleaser for cozy nights, school treats, or a sweet finish to family dinner. If you like trying different brownie ideas, you might also enjoy our cottage cheese protein brownies for a lighter twist.

Why Make This Recipe

Quick & Easy: Basic pantry staples and one bowl to mix.
Family Favorite: Kids love the marshmallows and Reese’s — perfect for parties.
Budget-Friendly: Uses a small number of affordable ingredients for big payoff.
Comfort Food: Warm, sweet, and nutty — it feels like a hug on a plate.

This recipe stands out because it pairs fudgy brownie base with melty marshmallows and salty-sweet Reese’s pieces. The contrast of textures — dense chocolate, pillowy marshmallow, and gooey peanut butter — sparks nostalgia and pure comfort. For a richer dessert idea, try our take on a decadent caramel brownie cheesecake.

Ingredients

For the brownie base:

1/2 cup (115g) unsalted butter, melted and slightly cooled
1 cup (200g) granulated sugar
2 large eggs, at room temperature
1 teaspoon vanilla extract
1/3 cup (35g) unsweetened cocoa powder
1/2 cup + 2 tbsp (75g) all-purpose flour (see variation for GF)
1/4 teaspoon salt
1/4 teaspoon baking powder (optional for a slightly cakier bite)

For the topping:

1 1/2 cups mini marshmallows or large marshmallows cut in half
1 cup chopped Reese’s peanut butter cups (about 8–10 regular cups)
1/2 cup semi-sweet chocolate chips (optional, for extra chocolate)

Helpful notes:

Use unsalted butter so you control the salt level.
Room-temp eggs blend easily and give a better texture.
Mini marshmallows melt faster and evenly.

How to Make Decadent Reese’s Marshmallow Brownies

Preheat the oven to 350°F (175°C). Grease an 8×8-inch pan and line it with parchment for easy removal. (Prep matters: lining makes clean slices.)
In a medium bowl, whisk melted butter and sugar until smooth. Add eggs and vanilla, mixing until glossy. (This helps create a fudgy crumb.)
Sift in cocoa powder, flour, salt, and baking powder. Stir until just combined — don’t overmix. (Overmixing makes brownies tough.)
Pour the batter into the prepared pan and spread it evenly. Sprinkle chocolate chips over the batter if using.
Bake 18–22 minutes, until the edges set and a toothpick in the center comes out with a few moist crumbs. (You want fudgy, not dry.)
Remove the pan from the oven. Immediately scatter the chopped Reese’s cups across the hot brownies, then press them lightly into the surface. Top with marshmallows, covering evenly.
Return the pan to the oven for 3–5 minutes, or broil 20–30 seconds on low to toast marshmallows — watch closely so they don’t burn. (This melts toppings and gives a golden top.)
Let the brownies cool at least 20 minutes so they set. Slice into squares and enjoy warm or at room temperature. (Cooling helps cleaner slices and less gooey mess.)

How to Serve Decadent Reese’s Marshmallow Brownies

Serve warm with a scoop of vanilla ice cream and a drizzle of chocolate sauce for a melting dessert.
Cut into small squares for a party platter; garnish with extra chopped Reese’s or a dusting of cocoa.
Pair with a glass of cold milk, coffee, or hot cocoa for a cozy afternoon treat.

How to Store Decadent Reese’s Marshmallow Brownies

At room temperature: Store in an airtight container for up to 2 days. Keep away from heat to avoid melting toppings.
In the fridge: Place in an airtight container for up to 5 days. Bring to room temp or warm briefly before serving.
In the freezer: Wrap squares individually and freeze up to 3 months. Thaw overnight in the fridge, then warm in a low oven or microwave.
To reheat: Microwave 10–20 seconds for a warm gooey center, or heat in a 325°F oven for 8–10 minutes.

Tips to Make Decadent Reese’s Marshmallow Brownies

Use an 8×8 pan for thick brownies; a 9×9 will cook faster.
Do not overbake — remove when the center still has moist crumbs.
Toast marshmallows under close watch or they will burn quickly.
Chop peanut butter cups evenly so every square gets flavor.
For neater slices, chill briefly, then cut with a hot, dry knife.

Variation

Gluten-free: Substitute a 1:1 gluten-free flour blend for all-purpose flour. The texture will be slightly different but still delicious.
nut-free alternative: Swap Reese’s with sunflower seed butter cups or dairy-free chocolate chips for allergy-friendly treats.

FAQ: Can I use whole peanut butter cups instead of chopping them?

Yes. You can place whole mini cups or halves on top, but chopped pieces spread flavor more evenly through each bite.

FAQ: How do I keep marshmallows from burning under the broiler?

Place the pan on the middle oven rack and broil on low for short bursts (10–20 seconds). Watch constantly — marshmallows can go from golden to burnt very fast.

FAQ: Can I make these ahead for a party?

Absolutely. Bake and cool the brownies, then store in the fridge. Add fresh marshmallows and a quick warm-up in the oven before serving for best texture.

Conclusion

These Decadent Reese’s Marshmallow Brownies bring rich chocolate, gooey marshmallows, and peanut-butter goodness into one cozy bar that people happily reach for again and again. They’re simple to make, great for family nights, and perfect for sharing at potlucks. If you want another take on Reese’s-style treats, check the original inspiration at Reese’s Marshmallow Brownies on Mom On Timeout. Please leave a comment and a star rating to tell us how they turned out, and share this recipe on Pinterest or Facebook so others can enjoy it too. What twist did you try? Let us know below!