This easy dessert has a layer of syrupy fruit with a crumb topping that's clumpy (a must for a crisp topping!), buttery, and you can make it ahead. The combination of flavors and textures is a mix of sweet and sour, soft and crisp. It's a must-try recipe!
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Great flavor combo
Desserts with crisp toppings are such favorites that we have a whole crisps and crumbles recipes category devoted to them.
Rhubarb is not easy to find where I am, so when I do, I like to bake a worthwhile dessert. This old-fashioned classic (a twist on the very vintage rhubarb crumble) feels like spring and early summer wrapped in a bowl, a far cry from its cozy counterpart, the popular apple oat crumble.
It's always a bit of kitchen magic to see the firm, bright pink (or sometimes green!) rhubarb stalks soften and break down in the oven. They go from quite firm to beautifully tender, creating that signature slightly pulpy texture in the filling.
Testing Notes
The key is to balance the sourness from the rhubarb. It's what makes this dessert unique. If you're working with particularly tart rhubarb or underripe strawberries, bump the sugar slightly or add a drizzle of honey.
Ratios matter, not just for the topping and filling, but also for the strawberries and rhubarb mixture. Start with a 1:1 fruit ratio. For a more tart taste, add more rhubarb; for a sweeter one, use more strawberries. I prefer a thick fruit layer compared to the amount of topping, but experiment to find what suits you best.
Should you peel the rhubarb? Only if the stalks are particularly thick and stringy. Most grocery store rhubarb is tender enough to use as-is.
Though I favor and encourage fresh, seasonal fruit, strawberries and rhubarb can be frozen and used directly from the freezer. I let the rhubarb thaw and drain it before using it for this recipe. Frozen fruit tends to release more liquid as it bakes, but this recipe has enough cornstarch in the filling to transform it into a wonderful syrup.
Ingredients
Quantities are listed on the recipe card towards the end of this post. The Ingredients page has more details and lists the brands we use.
- Fresh strawberries are always my first choice, but know that frozen ones work well and are perfect to make this dessert year-round.
- Fresh rhubarb: Look for firm, crisp, medium-thick stalks for the best texture, as large ones might be tougher and need to be peeled. Avoid limp or blemished ones. Color doesn't equal flavor-green rhubarb can be just as tasty as red. If using frozen rhubarb (not my first choice, but you can), don't thaw; use it straight from the freezer.
- Oats: I like rolled or traditional oats as they have more texture, but quick or instant oats also work.
- Sugar: I like the mix of white sugar for the topping (crunchiness) and brown sugar for the filling, giving it a caramel undertone. But you can use only one type for both layers (I tend to favor brown sugar).
- Fresh lemon juice has a much better flavor and sourness than bottled.
Steps to make strawberry rhubarb crisp
The fruit
Chopping your rhubarb and strawberries into roughly bite-sized pieces (half-inch at the most) ensures they cook evenly. And smaller bites are easier to eat.
Crumble topping
It's a simple method: we stir the dry ingredients together, cut in the butter pieces and mix everything until crumbly. And clumpy.
It can be made ahead and refrigerated for a week or frozen for a month. Break up the clumps before using.
Baking
When the fruit filling starts to bubble up, and the topping turns a golden brown, it means the juices are thickening, and the crumble is baking as it should.
If it starts browning too quickly, you can loosely tent the dish with foil.
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Strawberry Rhubarb Crisp with Oats
Ingredients
Crumble topping:
- ½ cup all-purpose flour
- ½ cup light brown sugar, packed
- ¾ cup old-fashioned oats, also called traditional oats or rolled oats
- 1 teaspoon fresh lemon zest, orange zest also works for a mellower flavor
- ½ teaspoon baking powder
- ¼ teaspoon salt
- ½ cup unsalted butter, melted and warm (not hot)
Fruit filling:
- 4 cups chopped strawberries
- 4 cups chopped rhubarb
- ¼ cup light brown or granulated sugar
- 2 teaspoons cornstarch
- 1 tablespoon fresh lemon juice, orange juice also works for a mellower flavor
Instructions
- Preheat the oven to 375°F (190°C) and lightly grease a 9x13 baking dish with soft butter or non-stick spray.
Make the crumb topping:
- In a medium mixing bowl, whisk ½ cup all-purpose flour, ½ cup light brown sugar, ¾ cup old-fashioned oats, 1 teaspoon fresh lemon zest, ½ teaspoon baking powder and ¼ teaspoon salt.
- Add ½ cup unsalted butter, melted, and stir until well combined. It should be the consistency of moist cookie dough. Refrigerate for 10-15 minutes while you make the filling.
Filling and assembly:
- Add 4 cups chopped strawberries and 4 cups chopped rhubarb to a large bowl. Dissolve 2 teaspoons cornstarch in 1 tablespoon fresh lemon juice and drizzle over the fruit. Sprinkle ¼ cup light brown or granulated sugar and toss to coat.
- Transfer the fruit to the baking dish and spread evenly. Cover the filling with the crumb topping. It's just easier to break it up with your fingers and drop little chunks of dough all over.
- Bake in preheated oven for 15 minutes, reduce the temperature to 350°F (180°C) and bake for about 20-25 more minutes. The topping will be golden brown and the filling will bubble.
- Let rest for 15-20 minutes. Serve with a dollop of fresh whipped cream or a generous scoop of vanilla ice cream.
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