Mississippi Mud Cake: Fudgy, Marshmallow-Gooey & Irresistibly Chocolatey
If you’re a serious chocolate lover, this Mississippi Mud Cake is your new signature dessert. Picture a super-moist chocolate sheet cake baked with mini marshmallows that melt into pockets of gooey sweetness, then finished with a thick, glossy fudge icing that sets into a shiny layer of bliss. Nostalgic, crowd-pleasing, and delightfully simple, it’s the dessert you’ll bring to potlucks, game days, and family dinners—and the one everyone will request again.
A Bite of History
The Mississippi Mud Cake earned its charming name from the dense, dark layers that resemble the rich, muddy banks of the Mississippi River. Born in the American South, it rose to fame as a back-of-the-pantry miracle—a cake that delivers bakery-level decadence using simple staples: flour, sugar, cocoa, butter, and marshmallows. Over time, bakers began finishing it with a warm, pourable fudge icing that seeps into every nook, setting into a glossy canopy. Today it’s a potluck icon and a weeknight indulgence with nostalgia baked into every square.
Ingredients & Why They Matter
- 1 cup all-purpose flour: Provides the cake’s structure and tender crumb.
- 1/2 cup mini marshmallows: Melt into gooey pockets for that signature mud-cake texture.
- 16 oz confectioners’ sugar: Creates a silky, pourable icing that sets to a glossy finish.
- 1/2 cup whole milk: Loosens the icing to the perfect drizzle-and-set consistency.
- 1/2 cup unsalted butter: Adds richness and flavor to both cake and icing (melt-in-your-mouth factor).
- 1/4 cup unsweetened cocoa powder: Packs a deep chocolate punch—use natural or Dutch-process.
- 1 teaspoon vanilla extract: Rounds out the chocolate with warmth and aroma.
- Chocolate cake batter (homemade or boxed): The no-fuss base—keep it simple without sacrificing flavor. Follow the package or your recipe for a 9×13-inch pan.
- Pinch of salt (optional): Balances sweetness and sharpens chocolate notes.
What Makes It Special
- Texture contrast: Soft cake, gooey marshmallows, and a set fudge top.
- Minimal effort: Pantry staples + sheet pan convenience.
- Make-ahead friendly: Tastes even better the next day.
- Feeds a crowd: Perfect 9×13 format for gatherings.
Step-by-Step Instructions
1) Prepare the Cake
- Preheat the oven to 350°F (175°C). Grease and flour a 9×13-inch baking pan.
- In a bowl, combine the flour and mini marshmallows.
- Prepare your preferred chocolate cake batter (homemade or boxed) according to its directions.
- Gently fold the flour–marshmallow mixture into the batter. Overmixing can deflate the batter and burst the marshmallows.
- Pour into the prepared pan and smooth the top for even baking.
2) Bake
- Bake for 25–30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs (not wet batter).
- Let the cake cool completely in the pan. A cooled surface ensures the icing sets beautifully on top rather than sinking in too deeply.
3) Make the Fudge Icing
- In a medium saucepan, combine confectioners’ sugar, whole milk, butter, and cocoa powder.
- Cook over medium heat, whisking constantly, until the mixture is smooth and glossy. Tiny sugar lumps will dissolve as it warms.
- Remove from heat and stir in the vanilla extract (and a pinch of salt, if using) to sharpen flavor.
4) Finish & Set
- Optional marshmallow layer: Scatter a small handful of mini marshmallows over the cooled cake for a soft top layer.
- Pour the warm icing evenly over the cake. Tilt the pan gently to help it flow into corners.
- Let the icing set 20–30 minutes before slicing. The top will become shiny and slice cleanly.
Why This Recipe is Loved
- Deep chocolate flavor with minimal ingredients.
- Signature gooey texture from marshmallows in the batter (and on top!).
- Glossy fudge icing that sets to a luscious, brownie-like finish.
- Beginner-friendly method—no special equipment required.
Pro Tips for Perfect Results
- Measure accurately: Too much flour leads to a dry cake. Spoon and level, or weigh.
- Don’t overbake: Pull the cake when a toothpick has moist crumbs—it keeps the crumb tender.
- Cool before icing: A cooled top = icing that sets glossy instead of disappearing.
- Texture control: For extra goo, add 1/4–1/2 cup more mini marshmallows to the top before icing.
- Flavor boost: Add 1 tsp espresso powder to the batter to intensify chocolate notes.
Pan, Batch & Party Tips
- Half batch: Bake in an 8×8-inch pan; check at 20–24 minutes.
- Cupcake format: Fill liners 2/3 full; bake 15–18 minutes. Spoon icing over cooled tops.
- Travel-friendly: Leave in the 9×13 pan, cover tightly, and transport with a cutting spatula.
Serving Suggestions
- Serve slightly warm with a scoop of vanilla ice cream or a dollop of whipped cream.
- Garnish with chopped pecans or walnuts for nutty crunch.
- Finish with chocolate curls, a dusting of cocoa, or a drizzle of salted caramel.
- Pair with espresso, cold brew, or a glass of cold milk to balance richness.
Make-Ahead & Storage
- Make ahead: Bake, cool, and ice the cake up to 1 day in advance; cover loosely so the icing surface doesn’t smudge.
- Room temp: Keeps well, covered, for 1–2 days.
- Refrigerator: Store up to 5 days. Bring slices to room temp for the best texture.
Freezing & Reheating
- Freeze (best un-iced): Wrap the cooled cake tightly and freeze up to 2 months. Thaw overnight in the fridge, then ice fresh.</ li>
- Freeze iced squares: Freeze slices on a tray until solid, then wrap. Thaw in the fridge and enjoy cold or room temp.
- Reheat: Warm individual slices in the microwave 10–15 seconds for a just-baked gooey vibe.
Tasty Variations
- Rocky Road: Add chopped pecans and chocolate chips to the batter.
- Mocha Mud: Mix 1–2 tsp instant espresso into the icing.
- Salted Peanut: Sprinkle salted peanuts over the warm icing for sweet-salty crunch.
- Double Cocoa: Use Dutch-process cocoa in both cake and icing for darker, smoother chocolate.
Mississippi Mud Cake – FAQ
Do I have to use mini marshmallows?
No, but they’re a hallmark of this cake’s gooey texture. You can omit them or replace with chocolate chips for extra fudginess.
Can I use a boxed cake mix?
Absolutely. A boxed devil’s food or chocolate fudge mix is a great shortcut. Fold in the flour and marshmallows as directed above for the classic mud-cake feel.
Why did my icing turn grainy?
It likely boiled or wasn’t whisked enough. Keep heat at medium and whisk until smooth; sift confectioners’ sugar to prevent lumps.
How do I keep the cake moist?
Don’t overbake, and store covered. The fudge icing acts as a moisture seal, keeping the crumb soft for days.
Can I make it nut-free?
Yes—simply skip any nut toppings and check your mix/ingredients for cross-contact warnings if needed.
Printable Recipe – Mississippi Mud Cake
Yield: 12–16 servings | Prep: 20 mins | Bake: 25–30 mins | Set: 20–30 mins
Ingredients
- 1 cup (120 g) all-purpose flour
- 1/2 cup (25 g) mini marshmallows, plus extra for topping (optional)
- 16 oz (454 g) confectioners’ sugar, sifted
- 1/2 cup (120 ml) whole milk
- 1/2 cup (113 g) unsalted butter, divided
- 1/4 cup (25 g) unsweetened cocoa powder
- 1 teaspoon vanilla extract
- Chocolate cake batter (homemade or boxed) for a 9×13-inch pan
- Pinch of salt (optional, for icing)
Instructions
- Heat oven to 350°F (175°C). Grease and flour a 9×13-inch pan.
- In a bowl, toss flour and mini marshmallows. Prepare chocolate cake batter as directed.
- Fold flour–marshmallow mix into batter; spread evenly in pan.
- Bake 25–30 minutes, until a toothpick comes out with moist crumbs. Cool completely in pan.
- For icing: In a saucepan whisk confectioners’ sugar, milk, 6 tbsp of the butter, and cocoa over medium heat until smooth. Remove from heat; stir in vanilla and a pinch of salt.
- Scatter extra mini marshmallows on the cooled cake (optional). Pour warm icing over the top and let set 20–30 minutes before slicing.
Final Thoughts
This Mississippi Mud Cake is proof that the most unforgettable desserts are often the simplest. With a deep chocolate crumb, gooey marshmallow pockets, and a shiny fudge icing that cuts cleanly, it delivers nostalgia and bakery-case drama in one easy pan. Keep it classic or play with the variations—either way, you’ll end up with a crowd-pleasing showstopper that tastes even better on day two. Bake it once, and it’ll earn a permanent place in your dessert rotation.
