My grandmother shared this vintage trick with me and it is a total game changer. You only need 4 ingredients to make this incredibly rich treat.

This slow cooker 4-ingredient cola cake is one of those vintage tricks that feels almost too simple to be real. My grandmother showed me how she used cola to make cakes extra moist and rich back when boxed mixes were a new thing, and it truly is a game changer on busy days. Everything comes together right in the slow cooker, and a can of cola stands in for the usual eggs and oil, giving you a dense, fudgy crumb with caramelized, bubbly edges and a shiny chocolate glaze on top. It’s the kind of no-fuss dessert you can toss together before dinner and let it quietly turn into something special while you go about your evening.

Serve this cola cake warm right out of the slow cooker, scooped into bowls so everyone gets some of the gooey center and the chewy, caramelized edges. A scoop of vanilla ice cream or a dollop of whipped cream melts into the warm cake and glaze in the best way. For something lighter, pair it with fresh berries or sliced strawberries to cut through the richness. It’s also lovely with a cup of coffee after Sunday dinner or a tall glass of cold milk for the kids. If you’re serving guests, you can sprinkle a little powdered sugar on each portion to dress it up without any extra work.

Servings: 8-10

1 (15.25-ounce) box chocolate cake mix

Lightly grease the inside of a 5- to 6-quart slow cooker with cooking spray or a thin layer of butter to help prevent sticking and make cleanup easier.

In a large mixing bowl, add the dry chocolate cake mix. Pour in the can of cola. Stir with a spatula or wooden spoon just until the batter is mostly smooth and no big dry pockets of mix remain. It will fizz a bit at first; that’s normal and part of the vintage cola trick.

Fold in 1 cup of the semisweet chocolate chips, stirring gently so they’re evenly distributed throughout the batter. This helps create that extra-rich, gooey texture in the finished cake.

Pour the batter into the prepared slow cooker and spread it into an even layer, making sure it reaches the edges so it cooks uniformly.

Drizzle the 1/2 cup caramel sauce over the top of the batter in a loose swirl or zigzag pattern. Do not stir it in; leaving it on top lets it sink and bubble as the cake cooks, creating caramelized pockets and edges.

Sprinkle the remaining 1/2 cup chocolate chips evenly over the surface of the batter. These will melt into a shiny, rich glaze as the cake cooks and rests.

Cover the slow cooker with the lid. Cook on HIGH for 2 to 2 1/2 hours, or on LOW for 3 1/2 to 4 hours, until the cake is set around the edges and the center looks mostly cooked but still a little glossy and soft. A toothpick inserted near the edge should come out with moist crumbs, while the center will be more gooey, like a lava cake.

Turn off the slow cooker and carefully remove the lid, tilting it away from you so the steam doesn’t hit your face or hands. Let the cake stand in the uncovered slow cooker for about 15 to 20 minutes. During this time, the melted chocolate chips on top will form a shiny glaze and the cake will firm up just enough while staying dense and moist.

If you like extra caramel flavor and a glossier top, drizzle a little more caramel sauce over the warm cake right before serving. Use a large spoon to scoop portions straight from the slow cooker, making sure each serving has some of the gooey center and the caramelized, bubbly edges.

Unplug the slow cooker after serving, and let any leftovers cool completely before covering and refrigerating them. Reheat individual portions in the microwave for 15 to 30 seconds until just warm and soft again.

For a slightly lighter version, you can use a cola with reduced sugar, but avoid diet sodas, as the artificial sweeteners don’t hold up well to long cooking and can affect both flavor and texture. If caramel isn’t a favorite in your house, swap the caramel sauce for the same amount of hot fudge topping or chocolate syrup, keeping the 4-ingredient structure intact. You can also use different chocolate cake mixes (devil’s food, dark chocolate, or German chocolate) to change the flavor profile while keeping the method the same. For picky eaters who don’t like visible chips, melt the full amount of chocolate chips with the caramel sauce in the microwave in short bursts, stir until smooth, and drizzle that over the batter so it bakes into a more uniform layer. For a nutty twist, you can sprinkle chopped pecans or walnuts over half the cake so those who like nuts can scoop from that side, though this will technically add a fifth ingredient. Food safety tips: Always make sure your slow cooker is in good working order and that the cord and plug are dry before use. Do not leave metal utensils resting inside the slow cooker while it’s on. Because this cake is very moist and dense, cool leftovers promptly and refrigerate them within 2 hours of cooking to prevent bacterial growth. Reheat only the portion you plan to eat, and discard any cake that has been left at room temperature for more than 2 hours after cooking or reheating. If you’re cooking with kids, keep them away from the hot sides of the slow cooker and the steam when removing the lid, as both can cause burns.