Fudgy Marshmallow Brownies
These brownies are the sort of dessert I make when I need something quick, comforting, and a little dramatic. The base is a boxed Betty Crocker Fudge Brownie mix so the texture stays reliably fudgy, and the marshmallow layer puffs into a glossy cloud that begs for a glossy chocolate frosting. It’s exactly the kind of recipe that looks like you worked harder than you did, which is the whole point on a busy weeknight or for last-minute guests.
I like to keep the process simple and precise: bake the mix as directed, top with marshmallows while the pan is still hot, and finish with a warm chocolate frosting that sets to a firm, shiny coat. The technique is straightforward, and the results are delightfully indulgent—melty inside, slightly chewy at the edges, with a pillowy top.
Below you’ll find a clear ingredient list pulled from the recipe, step-by-step instructions that follow the source directions exactly, and practical notes for troubleshooting, storing, and serving. No unnecessary substitutions unless you ask for them—just dependable brownies that make people smile.
Ingredient List
- 18.3ozpackage Betty Crocker Fudge Brownie Mix + Ingredients to prepare — The boxed mix provides the brownie base and any wet ingredients it calls for; follow the package for quantities and mixing order.
- 2c.marshmallows — Provides the pillowy top; sprinkle over the brownies while they’re hot so they soften and puff.
- 6Tbsphalf and half — Adds creaminess and helps make a glossy, spreadable frosting.
- 6Tbspbutter — Melts into the frosting for richness and shine; use unsalted if you want tighter control of seasoning.
- 1 1/2c.white sugar — Sweetens and helps the frosting set with the right texture; it is cooked briefly into a simple candy-like syrup.
- 1/2c.chocolate chips — Melted into the hot syrup to create the chocolate frosting; they give a smooth, chocolatey finish.
Fudgy Marshmallow Brownies — Do This Next
- Prepare the Betty Crocker Fudge Brownie Mix and bake in the pan called for on the package, following the package directions exactly; when baking is complete, remove the pan from the oven.
- Evenly sprinkle 2 cups marshmallows over the hot brownies. Turn the oven off, then return the pan to the hot, turned-off oven and close the door. Leave in the oven 2–3 minutes, until the marshmallows puff and soften, then remove the pan.
- While the marshmallows are puffing (or immediately after removing the pan), make the frosting: in a medium saucepan combine 6 tablespoons half and half, 6 tablespoons butter, and 1 1/2 cups white sugar.
- Heat the mixture over medium heat, stirring frequently to prevent scorching, until it comes to a boil. Once boiling, continue to boil for 1 minute while stirring.
- Remove the saucepan from the heat and immediately add 1/2 cup chocolate chips. Stir until the chocolate chips are fully melted and the frosting is smooth.
- While the frosting is still warm, spread it evenly over the marshmallow-topped brownies. Allow the frosting to set before cutting and serving.
The Upside of Fudgy Marshmallow Brownies
These brownies win on speed, texture, and presentation. Using the boxed mix keeps hands-on time low and guarantees a consistent fudgy crumb every time. The marshmallow layer adds a soft, cloud-like contrast to the dense brownie below, while the stovetop chocolate frosting gives a restaurant-style glossy finish that slices cleanly once set.
They’re also flexible for feeding a crowd. You can double the batch, bake in a larger pan, or make them the night before for an event—the components hold up well. For a last-minute dessert, you get maximum impact for minimal effort.
No-Store Runs Needed
If you already have a boxed brownie mix, marshmallows, butter, sugar, half-and-half, and chocolate chips, you are fully stocked for this recipe. The technique uses pantry staples and common dairy items, so it’s rare to have to run to the store specifically for these brownies.
If you’re out of one item and can’t shop, consider these minimal thoughts: marshmallows are the only truly unique item here—if you must skip them, the brownies will still be excellent with the frosting alone. But the marshmallows are what make this version special, so try to pick up a bag when you can.
Hardware & Gadgets
- Oven and the pan specified on the Betty Crocker package — follow the package pan size for correct bake time and depth.
- Mixing bowl(s) and a whisk or spoon — for preparing the boxed mix per package directions.
- Medium saucepan — for making the frosting; choose one with a thick bottom to reduce scorching.
- Spatula or offset spatula — to spread the hot frosting smoothly over the marshmallows.
- Measuring cups and spoons — to measure the half-and-half, butter, sugar, and chocolate chips precisely.
- Oven mitts and a cooling rack — for safe handling and cooling the pan.
Troubleshooting Tips
Marshmallows didn’t puff
They need residual oven heat. If they don’t puff, return the pan to the turned-off oven for another minute (watch closely) or briefly broil for just a few seconds—keep the door open so you don’t overdo it. If using mini marshmallows, they’ll generally puff faster than large ones.
Frosting is grainy or sugar didn’t dissolve
Stir continuously while heating to dissolve the sugar before it reaches a hard boil; a single minute of boiling after it comes to a boil is part of the method and helps the syrup set properly. If the sugar recrystallizes, rewarm gently and stir until smooth before adding the chocolate chips.
Frosting too thin or runny
If the frosting is still warm when you spread it, it will look thin but should set as it cools. If it refuses to set because it was overheated or liquid was added accidentally, allow it to cool briefly to thicken, then spread. If it stays loose, chill the pan briefly to help the top set—about 10–15 minutes in the refrigerator can firm it up without harming texture.
Brownies overbaked or too dry
Follow the package baking time and test with a toothpick; boxed mixes are forgiving, but ovens vary. If you’re consistently getting dry brownies, reduce bake time by a few minutes or check oven calibration.
Spring–Summer–Fall–Winter Ideas
Spring: Serve slices at room temperature with fresh berries on the side for brightness. The contrast between the rich chocolate and tart berries wakes the dish up.
Summer: Cut squares and offer cold vanilla ice cream alongside for an easy brownie sundae; the marshmallow and chocolate pair beautifully with cold cream.
Fall: Add a warm beverage—coffee or cider—and consider sprinkling a few toasted pecans over the frosting for texture (do this while the frosting is still tacky so they stick).
Winter: These brownies make a cozy party dessert. Serve warm from the fridge for cleaner slices, or heat single portions briefly to revive the marshmallow for an oozy treat.
Recipe Notes & Chef’s Commentary
The method here deliberately relies on residual and stovetop heat rather than complicated tempering or glazing. Turning the oven off and returning the pan softens marshmallows gently without browning, which preserves the white, pillowy look. The frosting is essentially a quick sugar syrup enriched with dairy and butter, then finished with chocolate chips for a smooth melt—timing matters, so add the chocolate immediately off the heat to prevent graininess and to achieve a glossy finish.
Half-and-half gives the frosting body without making it overly heavy; heavy cream works too if that’s what you have, but it’s not necessary. The 1-minute boil after the mixture reaches a boil is enough to concentrate the sugar so the frosting sets nicely once cooled.
Prep Ahead & Store
Make these brownies a few hours ahead or the day before. Allow them to cool completely, then store tightly covered at room temperature for up to 2 days. For longer storage, refrigerate in an airtight container for up to 5 days—bring to room temperature before serving for best texture.
Freezing: You can freeze cut squares individually wrapped, then stored in a freezer-safe container for up to 2 months. Thaw in the refrigerator overnight and then come to room temperature before serving. Note: the marshmallow layer is best fresh but will still be tasty after thawing.
Ask & Learn
If you want to adapt this recipe—different chocolate percentages, adding nuts, swapping in flavored marshmallows—ask and I’ll give practical guidance without changing the core method. Tell me what pantry items you have and I’ll suggest what will work or what to skip. Questions about oven temperatures, pan swaps, or how to scale the recipe are welcome; give me the pan size you plan to use and I’ll help with timing advice.
Bring It Home
These Fudgy Marshmallow Brownies are a reliable, crowd-pleasing finish to any meal. The boxed mix keeps them simple; the marshmallow and stovetop frosting elevate them to something memorable. Make them for a casual weeknight treat or for a celebration—either way, they deliver warm, chocolatey comfort and a little theatrical flourish that always earns compliments.
Fudgy Marshmallow Brownies
Ingredients
Ingredients
- 18.3 ozpackage Betty Crocker Fudge Brownie Mix + Ingredients to prepare
- 2 c.marshmallows
- 6 Tbsphalf and half
- 6 Tbspbutter
- 1 1/2 c.white sugar
- 1/2 c.chocolate chips
Instructions
Instructions
- Prepare the Betty Crocker Fudge Brownie Mix and bake in the pan called for on the package, following the package directions exactly; when baking is complete, remove the pan from the oven.
- Evenly sprinkle 2 cups marshmallows over the hot brownies. Turn the oven off, then return the pan to the hot, turned-off oven and close the door. Leave in the oven 2–3 minutes, until the marshmallows puff and soften, then remove the pan.
- While the marshmallows are puffing (or immediately after removing the pan), make the frosting: in a medium saucepan combine 6 tablespoons half and half, 6 tablespoons butter, and 1 1/2 cups white sugar.
- Heat the mixture over medium heat, stirring frequently to prevent scorching, until it comes to a boil. Once boiling, continue to boil for 1 minute while stirring.
- Remove the saucepan from the heat and immediately add 1/2 cup chocolate chips. Stir until the chocolate chips are fully melted and the frosting is smooth.
- While the frosting is still warm, spread it evenly over the marshmallow-topped brownies. Allow the frosting to set before cutting and serving.
Equipment
- Oven
- brownie pan
- Medium Saucepan
- Spatula
- Spoon
