While growing up in the Pacific Northwest, in the cool spring I learned to love rhubarb long before I could spell it. My dad grew more plants in the garden than we probably needed, but my mom and grandma happily baked all the stalks into delicious desserts and sauces. Rhubarb crisp with oatmeal was one of my grandma’s favorite rhubarb recipes (and in my memory it is second only to her pure rhubarb pie).
This rhubarb crisp recipe is still one of the first homemade desserts I make as soon as I can harvest stalks from my rhubarb plants, which I divided from my dad’s and transplanted to northwest Montana nearly 20 years ago. A crisp takes less work than rolling out pie crust and tastes just as delicious. The crunchy topping balances the soft fruit and almost screams for ice cream. When polishing off the leftover fruit with its granola-like topping for breakfast, leave off the ice cream to avoid feeling too guilty about starting your day with dessert.
Ingredients for Rhubarb Crisp
- Sugars: For the 1/2 cup brown sugar, choose dark brown sugar for a bolder molasses taste in the crumble topping or choose light or golden brown sugar for a hint of smoky caramel flavor. Otherwise, light and dark brown sugar have the same sweetness and texture.
- Cornstarch and flour: In this recipe for rhubarb crisp, cornstarch and flour act as thickeners, one soaking up the fruit juices and the other helping the topping cling together.
- Rhubarb: Look for firm, straight stalks with a slightly shiny surface when harvesting rhubarb or buying it at the store. The cut end will dry out the longer it sits, so use fresh rhubarb as soon as possible. Rhubarb that has been sliced, bagged and frozen works just as well as fresh in this recipe.
- Apples or strawberries: Counter rhubarb’s tartness with the natural sweetness of apples or strawberries. Because they both ripen in the spring, strawberry-rhubarb recipes are classic at that time of year. Apples make a tasty substitute if you have frozen rhubarb or get a second crop during the fall harvest.
- Oats: Rolled oats add crunch to the top of this rhubarb crisp recipe. They’re often the key difference between crumbles and crisps.
- Butter: When tossed with the topping ingredients and baked, butter turns the surface toasty and crunchy. Without it, the topping will be dry and coated with raw flour, which you don’t want.
- Cinnamon: Cinnamon enhances the taste of sweet fruit and baked goods.
Directions
Step 1: Prepare the fruit
Preheat the oven to 350°F. In a large bowl, combine the sugar and cornstarch. Add the rhubarb and apples or strawberries, and toss to coat. Spoon the mixture into an 8-inch cast-iron or other ovenproof skillet and spread it evenly.
Editor’s Tip: If you don’t have an ovenproof skillet, bake the crisp in an 8×8-inch or similarly sized baking pan that can withstand the oven’s heat. Ceramic or glass won’t react to the natural acidity of rhubarb as steel or aluminum bakeware might.
Step 2: Mix the topping
In a small bowl, combine the oats, brown sugar, butter, flour and cinnamon until the mixture resembles coarse crumbs.
Sprinkle the topping evenly over the fruit.
Step 3: Bake and serve
Bake the crisp until bubbly and the fruit is tender, about 45 minutes. If desired, serve it warm with ice cream.
Recipe Variations
- Keep it simple: If you love the tartness of rhubarb, you can make this recipe for rhubarb crisp from 5 cups sliced stalks without adding any extra sugar. The dessert is so simple that you can make a crisp with any fruit.
- Switch to honey: Substituting honey for sugar affects the texture of some baked goods, but not crisps. Mix just 2/3 cup honey into the fruit for the same sweetness, or cut back to even less depending on your taste. Honey would make the topping too sticky to sprinkle, so stick with brown sugar there.
- Add nuts: To give the topping even more crunch, replace half the oats with chopped nuts. Walnuts are more affordable than pecans, which have a richer flavor. Hazelnuts must be peeled before chopping.
How to Store Rhubarb Crisp
Let rhubarb crisp with oatmeal cool completely, and then transfer it to a container with an airtight lid, trying to keep the topping on the surface of the dessert. The crisp can be stored at room temperature for two days or in the refrigerator for up to five days. The topping will lose some of its crunchiness the longer it sits. Leftover crisp can be served at room temperature or returned to the ovenproof skillet and reheated in a low-temperature oven.
Can you freeze rhubarb crisp?
Fruit crisps, especially the top layer, get soggy when frozen, but fresh rhubarb freezes easily, allowing you to make quick crisps all year. To freeze rhubarb, slice it first. Thawed rhubarb works best so the filling doesn’t become too juicy.
Rhubarb Crisp Tips
How do you cut rhubarb for rhubarb crisp?
Cut rhubarb across the stalk so that you break the stringy strands that run up its length. The thinner the rhubarb slices, the more they will cook down in a crisp, so cut 1-inch pieces if you like chunks in your crisps and smaller slices for a smoother filling. You want to cut rhubarb only after you’ve harvested it; gently twisting and pulling is the best way to remove the stalks from the plant. Then, cut off each stalk’s top and broad leaf, and slice the stalks to use or freeze.
Why is the rhubarb crisp soggy?
To keep the topping from sinking and becoming soggy, thoroughly coat the flour and oats with butter. If bits still seem dry, mix in another tablespoon melted butter before you sprinkle the topping on the fruit. The beauty of this rhubarb crisp recipe is the crunchy topping layered over a soft base. For the crunchiest topping, let the crisp toast under the broiler for just a minute or two after it finishes baking, watching carefully to avoid burning the sugary surface.
How do you serve rhubarb crisp?
With vanilla ice cream, of course! Just scoop the crisp from the skillet into individual bowls and pile on the ice cream (crisp with ice cream can get a bit messy when served on plates). Rhubarb crisp with oatmeal is also delicious with a scoop of frozen lemon yogurt or fridge-cold Greek yogurt. This dessert is a delicious follow-up to some of these super-quick spring dinner ideas, which you can make and eat while the crisp is baking.
