Recipe

Mississippi Mud Cake

Dense chocolate sheet cake topped with gooey marshmallows and a glossy fudge frosting, with optional pecans for crunch.

By Matt Campbell

•

4.8

A freshly baked Mississippi mud cake in a metal sheet pan with a gooey marshmallow layer and glossy chocolate fudge frosting, kitchen counter background, natural window light

Mississippi Mud Cake is the dessert equivalent of showing up to the party in comfy clothes and still somehow being the best-dressed. It is a fudgy chocolate sheet cake with a gooey marshmallow layer that melts into all the nooks, then a warm, shiny chocolate fudge frosting poured on top like you mean it.

If you are used to lighter, fluffier chocolate cakes, this one is the contrast. It is dense and rich, closer to brownie energy than birthday cake energy. The good news is it is also low drama: one pan, simple ingredients, and you can slice it into a whole crowd’s worth of squares.

Square slices of Mississippi mud cake with marshmallow pull and chocolate frosting arranged on a serving platter for a party, indoor warm lighting

Why It Works

Deep chocolate flavor without fancy steps: cocoa plus hot coffee or water helps the cocoa dissolve smoothly so the cake tastes extra chocolatey.
Gooey marshmallow layer: marshmallows melt on the hot cake so you get that classic sticky layer without complicated filling.
Fudge frosting that sets like a dream: you pour it warm, it spreads easily, then firms up into sliceable, glossy squares.
Sheet cake math: one 9 x 13 pan feeds a crowd and travels well once cooled and set (aka the dessert you bring when you want people to remember your name).

Pairs Well With

Storage Tips

How to Store Mississippi Mud Cake

Room temperature: Cover the pan tightly and keep it in a cool, dry place for up to 1 to 2 days (skip the counter if your kitchen runs warm).
Refrigerator: For longer storage, cover and refrigerate for up to 5 days. Let slices sit at room temperature for 20 to 30 minutes before serving for the fudgiest texture.
Freezer: Cut into squares, wrap each piece in plastic wrap, then place in a freezer bag or container. Freeze up to 2 months. Thaw overnight in the fridge or for a few hours on the counter.

Party and Transport Tips

Let it set before you move it: Give the frosting at least 1 hour to cool and firm up so it does not smear.
Use the pan as the carrier: This cake is happiest traveling in the same 9 x 13 pan you baked it in. Cover with foil that does not touch the frosting, or use a high-lid carrier.
Clean cuts on-site: Bring a knife and wipe it between cuts. Warm water on the blade helps if the frosting is extra thick.

Common Questions

Is Mississippi mud cake the same thing as Mississippi mud pie?

Nope. Mud pie is usually a chilled, layered dessert with a cookie crust and mousse or pudding. Mud cake is typically a baked chocolate sheet cake with a marshmallow layer and fudge frosting, though you will see regional variations (nuts in the batter, no marshmallows, different frostings).

Do I have to use coffee in the cake batter?

You do not have to. Coffee mainly boosts the chocolate flavor. You can use hot water instead, or hot milk for a slightly softer crumb.

Marshmallows or marshmallow creme, which is better?

Both work. Mini marshmallows give you that classic bumpy, melty layer. Creme spreads more evenly, but it is a little trickier to dollop fast. If you use creme, warm the jar for a minute in hot water and lightly grease your spoon for easier scooping.

How do I keep the marshmallows from disappearing into the cake?

Let the cake bake fully, then add the marshmallows on top while the cake is hot. Give them just a few minutes in the oven to soften and puff, not long enough to fully liquefy and sink.

Can I make it ahead?

Yes. It is actually better a few hours after frosting because everything sets up. Make it the night before, cover, and serve the next day.

My frosting looks grainy. What happened?

Usually it is undissolved powdered sugar or cocoa. Sift the powdered sugar and cocoa next time, and whisk aggressively while the mixture is warm. If it still looks grainy, add 1 to 2 teaspoons of milk and keep whisking until glossy.

Matt Campbell

I have always had a huge passion for the culinary arts, people, working as a team, and so on. I wanted to pursue my love for cooking initially at Virginia Commonwealth University with a culinary arts degree; however, I instead decided to apply myself and acquire more practical skills. My end goal is to eventually open my own restaurant or similar establishment.

Kitchen Essentials

9 x 13 inch baking pan (metal works great for crisp edges, glass may need a few extra minutes)
Mixing bowls
Whisk and rubber spatula
Hand mixer or stand mixer (optional, but helpful for quick batter)
Medium saucepan (for the frosting)
Measuring cups and spoons
Offset spatula or spoon for spreading
Instant-read thermometer (optional, for doneness)

The first time I made Mississippi mud cake, I thought, this seems almost too easy for how legendary people act about it. Then I poured that warm fudge frosting over the marshmallow layer and watched it ripple into glossy little lakes. That is the whole vibe of this cake. It looks a little chaotic, feels like a sugar hug, and somehow tastes even better on a paper plate at a party when you are supposed to be “just having a small piece.”

Mississippi Mud Cake

(4.8 Reviews)

Prep Time 20 minutes

Cook Time 30 minutes

Total Time 1 hour 55 minutes

Servings 16 servings

Ingredients

For the Cake

1 3/4 cups all-purpose flour
2 cups granulated sugar
3/4 cup unsweetened cocoa powder
1 1/2 teaspoons baking powder
1 1/2 teaspoons baking soda
1 teaspoon fine salt
2 large eggs
1 cup buttermilk
1/2 cup neutral oil (canola or vegetable)
2 teaspoons vanilla extract
1 cup hot coffee or hot water

Marshmallow Layer

6 to 8 ounces mini marshmallows (about 3 to 4 cups), or 1 (7-ounce) jar marshmallow creme (use enough to cover the top)

Fudge Frosting

1/2 cup unsalted butter
1/3 cup milk (whole milk preferred)
1/4 cup unsweetened cocoa powder
1 teaspoon vanilla extract
3 1/2 cups powdered sugar, sifted
Pinch of salt
1/2 to 1 cup chopped pecans (optional)

Instructions

Prep the pan and oven. Heat oven to 350°F. Grease a 9 x 13 baking pan and line with parchment if you want super easy lifting and cleaner edges. (If you are using a glass pan, plan on adding a few minutes to the bake time.)
Mix the dry ingredients. In a large bowl, whisk together flour, granulated sugar, cocoa powder, baking powder, baking soda, and salt.
Add the wet ingredients. Whisk in eggs, buttermilk, oil, and vanilla until smooth.
Add the hot coffee or water. Slowly whisk in the hot coffee or hot water. This helps the cocoa dissolve smoothly and deepens the chocolate flavor. The batter will look thin. That is correct.
Bake. Pour batter into the prepared pan. Bake for 28 to 35 minutes, until a toothpick comes out with a few moist crumbs and not wet batter. Optional doneness check: the center should be about 200 to 205°F.
Add marshmallows. Pull the cake out and immediately scatter mini marshmallows all over the top (or dollop marshmallow creme in spoonfuls). Return to the oven for 2 to 4 minutes, just until the marshmallows puff and soften. If using creme, a lightly greased spoon makes this a lot less sticky.
Make the fudge frosting. In a medium saucepan over medium-low heat, melt butter. Whisk in milk and cocoa powder until smooth. Remove from heat, let it cool for 1 minute, then whisk in vanilla, powdered sugar, and a pinch of salt until glossy. If it is too thick to pour, add milk 1 teaspoon at a time.
Frost while warm. Pour the warm frosting over the marshmallow layer and gently spread. Sprinkle with chopped pecans if using.
Cool and slice. Let the cake cool at least 1 hour so the frosting sets. Slice into squares and serve.

Optional pro move: For extra clean slices, chill the cake for 20 minutes, then cut with a warm knife wiped clean between cuts.

Warm chocolate fudge frosting being poured from a saucepan onto a marshmallow-topped chocolate sheet cake in a baking pan, close up action shot

Nutrition information is estimated.

Did you make this? Tag @Mom's Best Recipes