This slow cooker 4-ingredient Mississippi mud cake is the kind of dessert that disappears before you can even grab a second slice. My brother actually requested this exact cake for his graduation barbecue, and by the time we were cleaning up, the pan was literally scraped clean. It’s rich, gooey, and ridiculously chocolatey, with a layer of melted marshmallows and toasted pecans on top that makes every bite feel extra decadent. Since it all comes together in the slow cooker with just four pantry-friendly ingredients, it’s perfect for busy days when you want a crowd-pleasing dessert without hovering over the oven.
Serve this Mississippi mud cake warm right out of the slow cooker so the marshmallows stay gooey and the chocolate stays fudgy. Spoon it into bowls and pair with a scoop of vanilla ice cream or a dollop of whipped cream if you want to lean into the over-the-top decadence. It’s great with coffee after a big family dinner, or alongside cold milk at a casual barbecue. Keep the cake in the slow cooker on the “warm” setting during parties so guests can help themselves to a cozy, scoopable dessert all evening.
Slow Cooker 4-Ingredient Mississippi Mud CakeServings: 10-12
Ingredients
1 (15.25-ounce) box chocolate fudge cake mix
1 1/4 cups chocolate fudge frosting (from a 16-ounce tub, about 3/4 of the container)
2 cups mini marshmallows
1 cup chopped pecans
Directions
Lightly grease the inside of a 5- to 6-quart slow cooker with nonstick cooking spray or a thin layer of butter to help the cake release and make cleanup easier.
In a large mixing bowl, combine the dry chocolate fudge cake mix and the chocolate fudge frosting. Use a sturdy spatula or wooden spoon to stir and press the mixture together until it forms a thick, sticky batter. It will be much thicker than a traditional cake batter, more like brownie dough.
Scrape the thick chocolate batter into the prepared slow cooker. Use the spatula to spread it into an even layer, making sure it reaches all the edges so it cooks evenly.
Cover the slow cooker with the lid and cook on LOW for 2 1/2 to 3 hours, or until the edges look set and slightly pulled away from the sides and the center is just barely set but still looks glossy and soft. Avoid lifting the lid during the first 2 hours so the cake can bake properly.
Once the cake is mostly set but still fudgy in the center, quickly sprinkle the mini marshmallows evenly over the top of the hot cake, followed by the chopped pecans, covering as much surface as possible.
Place a clean kitchen towel or a couple of layers of paper towels over the slow cooker insert, then put the lid back on top. This helps catch condensation so it doesn’t drip back onto the marshmallows and make them watery.
Continue to cook on LOW for 10 to 15 minutes, just until the marshmallows are melted, puffy, and sticky and the pecans are warmed and lightly toasted. Check after 10 minutes so they don’t over-melt or scorch.
Turn off the slow cooker and let the cake sit, uncovered, for about 10 minutes to slightly firm up while still staying very gooey and scoopable. Serve warm straight from the slow cooker by spooning portions into bowls, making sure each serving gets plenty of melted marshmallow and pecans on top.
Variations & Tips
To make this cake your own while still keeping it simple, you can swap the chocolate fudge cake mix for devil’s food or dark chocolate for a slightly different flavor, or use a different chocolate frosting style (like milk chocolate) for a sweeter finish. If you’re not a fan of pecans, try chopped walnuts, almonds, or even leave the nuts off and add an extra 1/2 cup of mini marshmallows for an ultra-gooey top. For a s’mores twist, sprinkle a handful of crushed graham crackers over the marshmallows and pecans during the last few minutes of cooking. If you need to make it nut-free, simply omit the pecans and consider adding chocolate chips on top instead; just be sure to clearly label the dessert if serving to a crowd so guests with allergies know what’s in it. For a little flavor boost, you can stir 1 teaspoon of instant espresso powder into the dry cake mix before adding the frosting to deepen the chocolate flavor without adding any new ingredients to the final count. Food safety tips: Always cook the cake on LOW as directed and avoid lifting the lid early, since frequent opening can affect cooking time and leave the center undercooked. Use a clean spoon each time you serve from the slow cooker to avoid cross-contamination at parties. Once everyone has eaten, turn the slow cooker off and let leftovers cool, then transfer them to an airtight container and refrigerate within 2 hours; reheat individual portions in the microwave until just warm and gooey before serving.
