Dump frozen whole blackberries in the slow cooker and 3 other ingredients to get a dessert so delicious your family will be begging for more.

This 4-ingredient slow cooker Father’s Day blackberry treat is the kind of low-effort, high-reward dessert I lean on when the day is busy but I still want something a little special. Frozen whole blackberries go straight into the slow cooker—no thawing, no fuss—then get topped with a buttery, cake-like layer that bakes up soft underneath and lightly crisp on top. It’s a cousin of old-fashioned cobblers and dump cakes that home cooks have been making in the Midwest for decades: simple pantry staples, minimal dishes, and a warm, spoonable dessert that feels celebratory without keeping you tied to the oven.

Serve this warm right out of the slow cooker, spooned into bowls. A scoop of vanilla ice cream is classic, but lightly sweetened whipped cream or vanilla yogurt work nicely too. I like to add a sprinkle of toasted almonds or granola for crunch. Coffee pairs beautifully with the deep berry flavor, and if you’re serving this after a Father’s Day cookout, it’s a lovely contrast to grilled meats and simple sides like a green salad or corn on the cob.

Servings: 6

6 cups frozen whole blackberries (about 28–32 ounces)

Lightly coat the inside of a 5- to 6-quart slow cooker with nonstick cooking spray or a thin layer of butter to help prevent sticking.

Dump the frozen whole blackberries into the bottom of the slow cooker, spreading them into an even layer. They should still be frozen; do not thaw.

Sprinkle the granulated sugar evenly over the frozen blackberries. This helps sweeten the fruit and draw out the juices as they cook.

Evenly sprinkle the dry yellow cake mix over the sugared blackberries, covering the fruit completely. Do not stir; leaving the layers intact helps create distinct juicy fruit on the bottom and a tender topping.

Slowly drizzle the melted butter over the dry cake mix, trying to moisten as much of the surface as possible. It’s fine if a few dry spots remain; steam in the slow cooker will help hydrate them as it cooks.

Cover the slow cooker with the lid and cook on HIGH for 2 1/2 to 3 hours, or on LOW for 4 to 5 hours, until the blackberries are bubbling around the edges and the topping is set and mostly cooked through. The top may look a bit uneven or slightly moist in spots—that’s normal for a slow cooker dessert.

Turn off the slow cooker and let the dessert rest, covered, for 15 to 20 minutes. This allows the juices to thicken slightly and makes it easier to spoon out clean portions.

Spoon the warm blackberry dessert into bowls and serve as is, or top with vanilla ice cream, whipped cream, or yogurt.

For a slightly tangier dessert, swap half of the granulated sugar for light brown sugar or add 1 to 2 teaspoons of lemon juice directly over the frozen berries before adding the sugar. If you prefer a less sweet treat, reduce the sugar to 1/2 cup; the blackberries will shine a bit more. You can also use a white cake mix instead of yellow for a lighter flavor, or a lemon cake mix if you like a bright, citrusy note with the berries. For a nutty crunch, sprinkle 1/2 cup chopped pecans or sliced almonds over the cake mix before drizzling on the butter. If you’re cooking for someone who is dairy-free, use a dairy-free cake mix (many standard brands already are) and substitute a neutral vegetable oil or melted dairy-free butter for the melted butter; use 1/2 cup oil, drizzled evenly. To make individual servings feel more composed, spoon the warm blackberry mixture into small ramekins and top each with a dollop of Greek yogurt and a sprinkle of granola. Food safety notes: Always start with properly frozen blackberries from a trusted source; keep them frozen until you’re ready to add them to the slow cooker. Do not leave the finished dessert on the “warm” setting for more than 2 hours to avoid bacterial growth; after that, cool leftovers quickly and refrigerate in a shallow container. Leftovers should be refrigerated within 2 hours of cooking and eaten within 3 to 4 days. Reheat portions thoroughly until steaming before serving. If you’re serving this to young children, older adults, or anyone with a compromised immune system, avoid adding raw egg-based toppings (like some homemade whipped toppings) unless they are made with pasteurized eggs.