This tart and sweet rhubarb crisp, finished with a crunchy whole-grain oat topping, is the ultimate spring dessert—especially with a scoop of creamy vanilla ice cream.
Every spring I like to share a fresh rhubarb recipe—rhubarb is one of those bright, seasonal ingredients that can be tart, sweet, and endlessly versatile. Around here it grows abundantly, so I often have more than I can use fresh. I freeze some for later, but I also try to bake a variety of easy rhubarb desserts while it’s in season.
I keep this crisp simple and wholesome by using a whole-grain flour and an oat-forward topping. Old-fashioned oats give the topping a satisfying chew, and using a whole-grain or oat flour adds a nutty depth that pairs beautifully with the tangy fruit.
Ingredients for Rhubarb Crisp
For the Rhubarb Filling
- 1.5 pounds rhubarb (about 4–5 cups, chopped)
- 1/4 cup granulated sugar
- 2 tablespoons all-purpose flour or cornstarch
- 1 tablespoon lemon juice
- 1 teaspoon vanilla extract
For the Topping
- 1/2 cup flour (use oat flour or another whole-grain flour to keep it gluten-free)
- 1/2 cup old-fashioned oats
- 1/2 cup packed brown sugar
- 1/2 teaspoon ground cinnamon
- 1/2 teaspoon ground cardamom (optional)
- Pinch of salt
- 4 tablespoons very cold butter
I like adding a touch of cardamom to the topping for a subtle warm floral note, but cinnamon alone works perfectly well if you don’t have cardamom on hand. If you want to make the recipe entirely gluten-free, use gluten-free oats and oat flour or another certified gluten-free flour.
How to Make Rhubarb Crisp
1. Wash the rhubarb and cut it into bite-size pieces.
2. In a medium bowl, combine the chopped rhubarb with 1/4 cup sugar, 2 tablespoons flour (or cornstarch), lemon juice, and vanilla. Toss gently to coat.
3. Let the mixture rest in a colander placed over a bowl for a couple of hours to drain off excess liquid. This step helps keep the topping from getting soggy; you can discard the collected liquid.
4. For the topping, whisk the flour, oats, brown sugar, cinnamon, cardamom (if using), and a pinch of salt in a small bowl.
5. Using a large-holed cheese grater or a pastry cutter, grate or cut the very cold butter into the dry topping ingredients until the mixture resembles coarse crumbs.
6. Press the mixture lightly with your fingers to form clumps; chill the topping in the refrigerator until you’re ready to bake.
When ready to bake:
7. Preheat the oven to 375°F (190°C).
8. Lightly grease an 8″ x 8″ (2.5‑quart) baking dish or similar casserole dish.
9. Use a slotted spoon to transfer the drained rhubarb into the prepared dish, leaving excess liquid behind in the colander.
10. Evenly sprinkle the chilled oat mixture over the rhubarb.
11. Bake for about 45 minutes, until the topping is golden brown and the rhubarb is bubbling around the edges.
12. Let the crisp cool slightly before serving. It’s excellent warm with vanilla ice cream or a dollop of whipped cream.
How to Prevent a Soggy Rhubarb Crisp
Rhubarb releases a fair amount of juice when it sits and when it bakes. To avoid a soggy topping, allow the rhubarb to sit coated with sugar, flour (or cornstarch), and lemon to macerate for a while, then drain it in a colander. The drained liquid can be discarded. This step reduces excess moisture and helps the oat topping stay crisp and golden.
If you’re short on time you can skip the long drain, but expect the finished crisp to be juicier and the topping a bit softer.
Can you use frozen rhubarb?
Yes — frozen rhubarb can be used successfully, but thaw and drain it well before baking to remove extra liquid. Follow the same coating and draining steps to prevent the filling from becoming too watery.
Notes and Storage
Rhubarb crisp is best enjoyed the day it’s baked when the topping is at its crispiest. If you don’t mind a softer topping, the crisp will keep for a few days in the refrigerator. Reheat individual portions briefly in the oven or microwave before serving.
To make the recipe gluten-free, choose certified gluten-free oats and a gluten-free flour such as oat flour or a commercial gluten-free blend. Cardamom is optional but brings a lovely aromatic note—cinnamon alone is a fine substitute.
Nutrition Highlights (Approximate)
Per serving (recipe yields about 6): approximately 363 calories, 9 g total fat, 67 g carbohydrates, 4 g fiber, and 4 g protein. These values are estimates and will vary based on exact ingredient choices and portion size.
Rhubarb’s bright tartness balances the sweet, crunchy topping perfectly, making this crisp a reliably popular spring dessert. Serve it warm with vanilla ice cream, and enjoy the contrast of temperatures and textures.
What are your favorite ways to enjoy rhubarb?
Try this crisp as a starting point and experiment with additions like a handful of berries, a splash of orange juice in the filling, or a sprinkle of chopped nuts in the topping. Seasonal fruit and small tweaks can create new, delicious variations.