This slow cooker 4-ingredient s'mores dump cake is my lazy-day version of the gooey pan my grandpa used to make on our annual camping trips. He’d layer everything right in a battered old baking pan, set it over the campfire grate, and we’d all stand around waiting for the marshmallows to puff and the chocolate to melt into little pools. By the time it came off the fire, the whole pan disappeared in minutes—no plates, just spoons and happy kids. This slow cooker version keeps that same rich, sticky, graham-and-chocolate magic, but it’s easy enough for any home cook: no campfire, no fuss, and only four simple ingredients you can keep in the pantry.
Serve this s'mores dump cake warm right out of the slow cooker, scooped into bowls so you catch the gooey marshmallow top, the melted chocolate, and the soft graham cracker cake in every spoonful. It pairs nicely with a small scoop of vanilla ice cream or a dollop of whipped cream if you want to cool down all that richness. A cup of coffee, hot cocoa, or cold milk is just right alongside, especially if you’re sharing it on the porch after supper. Let folks eat it casually—this is a family-style, pass-the-spoon kind of dessert, not a fussy one.
Slow Cooker 4-Ingredient S'mores Dump CakeServings: 8-10
Ingredients
1 box (15.25 ounces) yellow cake mix (dry, unprepared)
1/2 cup (1 stick) unsalted butter, melted
2 cups semi-sweet chocolate chips
4 cups mini marshmallows
Directions
Lightly grease the bottom and lower sides of a 5- to 6-quart slow cooker with butter or nonstick spray. This helps the gooey edges release and keeps cleanup simple.
Sprinkle the chocolate chips evenly over the bottom of the slow cooker to form a solid chocolate layer. This will melt into rich pools as it cooks.
In a medium bowl, stir together the dry yellow cake mix and the melted butter until the mixture looks like soft, slightly crumbly, damp sand. It should hold together when you pinch it but still be easy to sprinkle.
Gently scatter the buttery cake mixture evenly over the chocolate chips. Do not stir or press it down firmly; just spread it out in an even layer so the heat can move through and create a soft, graham cracker–like cake layer.
Sprinkle the mini marshmallows evenly over the top of the cake mixture, covering as much of the surface as you can. This will create that gooey, toasty marshmallow blanket on top.
Cover the slow cooker with its lid. Cook on HIGH for 2 to 2 1/2 hours, or until the edges are set and lightly browned, the chocolate is melted and bubbly around the sides, and the marshmallows are puffed and golden in spots. Avoid lifting the lid during the first 1 1/2 hours so the heat stays trapped.
If your slow cooker tends to run hot and the marshmallows brown too quickly, you can place a sheet of foil loosely under the lid (shiny side up) to prevent scorching, or switch to LOW during the last 30 minutes. The center should still be soft and gooey, like a molten cake.
Once done, turn off the slow cooker and let the dessert rest, uncovered, for about 10 minutes. This gives the molten layers a chance to thicken slightly while staying wonderfully gooey.
Serve warm, scooping straight from the slow cooker with a large spoon. Be sure to dig all the way to the bottom so each serving has toasted marshmallow, soft graham-like cake crumbles, and melted chocolate pools, just like that campfire pan my grandpa used to make.
Variations & Tips
To lean even more into the campfire flavor, you can substitute a graham cracker cake mix if you find one, or stir 1/2 cup of very finely crushed graham crackers into the dry yellow cake mix before adding the melted butter (this will technically add a fifth ingredient, but the basic recipe works beautifully with just the four listed). You can also swap part of the chocolate chips for milk chocolate chips if you like your s'mores a bit sweeter, or use dark chocolate chips for a deeper, less sugary bite. For a nutty twist, sprinkle 1/2 cup chopped toasted pecans or peanuts over the chocolate chip layer before adding the cake mixture. If you prefer a slightly less gooey center, cook closer to 2 1/2 hours and let it stand 15 to 20 minutes before serving. Food safety tips: Always make sure your slow cooker is in good working order and use the HIGH setting as directed so the dessert heats quickly into a safe temperature zone. Do not leave the finished dessert sitting on the WARM setting for more than 2 hours; after that, refrigerate leftovers in a shallow container and reheat portions gently in the microwave or at LOW in the slow cooker until warmed through. Keep children away from the hot crock and lid, as steam and melted sugar can cause burns.
