When rhubarb is in season, a slow cooker dessert like this is an easy way to turn a tart stalk into something soft, jammy, and deeply comforting with very little hands-on work. This simple four-ingredient recipe leans on rhubarb’s natural tang and pairs it with sugar and a cake mix-style topping for a cobbler-like dessert that feels old-fashioned in the best way, while the slow cooker keeps the kitchen cool on warm summer days.
Serve this warm on its own or spooned into bowls with vanilla ice cream, lightly sweetened whipped cream, or a dollop of plain Greek yogurt for a pleasant contrast. If you want to round it out for a casual summer meal, it fits nicely after grilled chicken, burgers, or a simple picnic spread, and a cup of coffee or iced tea alongside makes it especially nice.
4-Ingredient Slow Cooker Summer Rhubarb Dessert
Servings: 6 to 8
Ingredients
5 cups raw rhubarb, sliced into 1/2-inch pieces
1 cup granulated sugar
1 box yellow cake mix, about 15.25 ounces
1/2 cup unsalted butter, melted
Directions
1. Lightly grease the inside of a 4- to 6-quart slow cooker. Spread the sliced rhubarb evenly across the bottom.
2. Sprinkle the granulated sugar evenly over the rhubarb so the fruit is well coated.
3. Scatter the dry cake mix evenly over the sugared rhubarb, covering the surface as uniformly as possible. Drizzle the melted butter all over the top.
4. Cover and cook on High for 2 to 3 hours or on Low for 4 to 5 hours, until the rhubarb is very tender and the topping is set and golden around the edges.
5. Let the dessert rest uncovered for 15 to 20 minutes before serving so the juices thicken slightly. Spoon into bowls and serve warm.
Variations & Tips
Add cinnamon: A light sprinkle of ground cinnamon over the sugar adds warmth and makes the dessert feel a bit more like a cobbler. About 1/2 teaspoon is enough to support the rhubarb without overpowering it.
Try strawberries: Replace 1 to 2 cups of the rhubarb with sliced strawberries for a classic strawberry-rhubarb combination. This softens the tartness and gives the filling a sweeter, fruitier flavor.
Keep the topping even: For the best texture, drizzle the butter as evenly as you can over the cake mix. A few dry spots are normal in slow cooker desserts, but broad coverage helps the topping cook up more evenly.
Watch your slow cooker: Slow cookers vary quite a bit, so start checking on the early side. If the edges are getting deeply browned and the fruit is bubbling, it is ready even if your cooker usually runs a little hot.
Use frozen rhubarb if needed: Frozen sliced rhubarb works well when fresh is unavailable. Use it straight from frozen, but expect a slightly looser filling and possibly a little extra cooking time.