This slow cooker 5-ingredient poor man rhubarb crisp is exactly what I reach for when spring rhubarb shows up and I don’t want to fuss. It leans into pantry basics and that unmistakable tub of cheap yellow margarine most of us grew up with, and it’s built around frozen chopped rhubarb so you don’t even have to prep the stalks. Everything is simply dumped into the slow cooker—no mixing bowls, no creaming, no fancy technique—then left to bubble into a soft, tangy-sweet dessert with a buttery, oat-crisped top. It’s very much a Midwestern-style “dump dessert,” born from potlucks and church basements where practicality and thrift matter just as much as flavor.
Serve this rhubarb crisp warm right out of the slow cooker, spooned into shallow bowls so you catch plenty of syrupy juices and soft fruit. A scoop of vanilla ice cream, a dollop of whipped cream, or even a splash of half-and-half over the top gives a nice contrast to the tart rhubarb. It pairs nicely with simple grilled or roasted dinners—think roast chicken, pork chops, or a pot of chili—because the bright, tangy sweetness feels like a refreshing finish. Leftovers are lovely at room temperature with plain yogurt for a not-too-fancy brunch or coffee break.
Slow Cooker 5-Ingredient Poor Man Rhubarb CrispServings: 6
Ingredients
6 cups frozen chopped rhubarb (unthawed)
1 cup granulated sugar
1 cup quick-cooking oats
1/2 cup all-purpose flour
1/2 cup cheap yellow margarine, melted or very soft (plus a little extra for greasing, optional)
Directions
Lightly grease the inside of a medium slow cooker (4- to 6-quart) with a little margarine if you like, just to help with cleanup and prevent sticking.
Spread the frozen chopped rhubarb evenly in the bottom of the slow cooker. Do not thaw the rhubarb; it should go in straight from the freezer so it releases its juices slowly as it cooks.
Sprinkle the granulated sugar evenly over the rhubarb so it forms a loose, sweet layer on top of the fruit.
In a small bowl (or right in a measuring pitcher), stir together the quick-cooking oats and all-purpose flour just to combine. This simple mix will form the crisp-style topping as it cooks.
Scatter the oat-and-flour mixture evenly over the sugared rhubarb. Don’t worry if some falls down between the pieces of fruit; it will help thicken the juices.
Take your cheap yellow margarine and, using a spoon or your hands, dollop or pour it all over the top of the oat mixture and rhubarb. You’re essentially dumping the margarine over the frozen chopped rhubarb and dry ingredients so it can melt down and moisten everything 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 rhubarb is very soft and bubbling and the top looks set and glossy with pockets of lightly crisped oats.
Once cooked, turn off the slow cooker and let the rhubarb crisp sit, covered, for about 15 to 20 minutes. This rest helps the juices thicken slightly so the dessert isn’t too runny when you serve it.
Spoon the warm rhubarb crisp into bowls and serve as-is or with ice cream, whipped cream, or plain yogurt.
Variations & Tips
You can play with this basic 5-ingredient framework while keeping the spirit of the recipe intact. If you’d like a little spice, add 1 teaspoon of ground cinnamon or 1/2 teaspoon of ground ginger to the oat-and-flour mixture before dumping it over the rhubarb. For a slightly richer texture, swap half of the granulated sugar for light brown sugar, which will add a hint of caramel flavor. If your rhubarb is especially tart and you prefer a sweeter dessert, increase the sugar by 1/4 cup. To stretch the fruit, you can replace up to 2 cups of rhubarb with frozen strawberries or raspberries; just keep the total amount of fruit at about 6 cups. For a firmer, more defined topping, reduce the cooking time toward the shorter end and peek once near the end to make sure it doesn’t overcook into a fully soft pudding-like texture. Food safety tips: Always start with rhubarb that has been properly washed and chopped before freezing, and discard any leaves (they are not edible). Keep the frozen rhubarb in the freezer until you’re ready to assemble the crisp; do not let it sit at room temperature for long periods. Cook the dessert until it is fully hot and bubbling throughout to ensure it reaches a safe temperature, and refrigerate leftovers within 2 hours of cooking in a shallow container. Reheat leftovers thoroughly before serving, and consume within 3 to 4 days.
