Strawberry Rhubarb Crisp with a Buttery Oat Topping

A strawberry rhubarb crisp is the dessert that makes the most of spring fruit. Sweet strawberries and tart rhubarb bake down into a jammy filling under a crumble that stays buttery and crisp.

It comes together in about an hour, and most of that time is hands-off in the oven. Serve it warm with a scoop of vanilla ice cream, and you have a dessert that feels just right for a weeknight and still gets compliments at a barbecue.

What Makes This Strawberry Rhubarb Crisp So Good

The combination of tart rhubarb and sweet strawberries is the one I come back to every spring. You end up with a filling that is jammy but not cloying, with the rhubarb keeping everything bright.

The topping is all about that contrast. A buttery oat and brown sugar crumble keeps its crunch even after it cools, and I leave some larger bits of butter in the mixture so you get those tender pockets everyone fights over.

Ingredients

• 1 lb fresh rhubarb, sliced 1/2 inch thick: look for firm, pink stalks for the best color.
• 1 lb fresh strawberries, hulled and quartered: ripe but not mushy.
• 3/4 cup granulated sugar: adjusts the sweetness; rhubarb needs sugar to balance its tartness.
• 1/4 cup cornstarch: thickens the juices.
• 1 tablespoon lemon juice: cuts through the sweetness.
• 1 teaspoon vanilla extract: rounds out the flavor.
• 1/2 teaspoon salt, divided: half for the fruit, half for the topping.
• 1 cup old-fashioned rolled oats: not instant, so the topping stays crisp.
• 3/4 cup all-purpose flour: spooned and leveled.
• 1/2 cup packed light brown sugar: gives the topping a deep, caramel note.
• 1/2 teaspoon ground cinnamon: adds a little warmth, optional but nice.
• 1/2 cup unsalted butter, cold and cut into small cubes: you can use salted butter and omit the salt.

Variations / Substitutions

• Frozen fruit: you can use frozen rhubarb and strawberries; thaw and drain them first to avoid a watery filling.
• Gluten-free: swap in a 1:1 gluten-free flour blend and certified gluten-free oats.
• Refined sugar-free: replace the brown sugar with coconut sugar and the granulated sugar with maple syrup, cutting the syrup back to 1/2 cup and reducing the lemon juice by a teaspoon.
• Spice it differently: add a pinch of nutmeg or cardamom along with the cinnamon for a different warmth.

If you like this, my Blueberry Peach Crumble is another favorite for stone fruit season.

How to Make Strawberry Rhubarb Crisp

Step 1: Toss and Macerate the Fruit

Combine the rhubarb, strawberries, 3/4 cup granulated sugar, cornstarch, lemon juice, vanilla, and half the salt in a large bowl. Toss until everything is coated, then let the fruit sit for about 10 minutes while you preheat the oven to 375°F (190°C).

After 10 minutes, the fruit will look glossy and a little syrupy, with the sugar starting to pull out the juices. That is exactly what you want for a jammy filling.

Step 2: Work the Butter into the Oat Topping

In another bowl, stir together the oats, flour, brown sugar, cinnamon, and remaining salt. Add the cold butter cubes and use your fingertips or a pastry cutter to work the butter into the dry mix for 2 to 3 minutes. Stop when it looks like coarse crumbs with some pea-sized butter pieces still visible.

The mixture should feel clumpy when you squeeze it, with streaks of butter running through. Those butter pockets melt in the oven and create a crisp, craggy top.

Step 3: Layer the Fruit and Crumble

Scrape the fruit and all the accumulated juices into a 9-inch square baking dish, spreading it evenly. Grab handfuls of the topping and squeeze them lightly before breaking them apart over the fruit, which creates bigger, craggy clusters that bake up extra crisp.

Cover the fruit completely but don’t pack the topping down. A few gaps where the filling peeks through are fine, they will bubble up and look beautiful.

Step 4: Bake Until Golden and Bubbling

Set the dish on a rimmed baking sheet to catch any juices, then bake for 35 to 40 minutes. The topping should turn deeply golden brown and the fruit should bubble thickly around the edges.

You will smell the sweet-tart aroma and see the juices thicken against the sides of the dish. If the topping browns too quickly before the filling is done, loosely tent the crisp with foil for the last 10 minutes.

Step 5: Spoon and Serve Warm

Let the crisp rest on a wire rack for at least 10 minutes so the filling can set up a little. Then spoon it into bowls while it is still warm.

A scoop of vanilla ice cream melts right into the warm fruit, and a dollop of whipped cream works beautifully too.

A Few Notes Before You Start

• If your rhubarb stalks are very thick, peel away any tough outer strings with a paring knife, the same way you would peel celery.
• For an even crunchier topping, sprinkle 1 tablespoon of demerara sugar over the crumble just before it goes into the oven.
• Taste a piece of raw rhubarb. If it is exceptionally sour, add an extra tablespoon of granulated sugar to the filling.
• Grate the cold butter on the large holes of a box grater if you want to cut it in faster, just work quickly so it stays cold.

Bake times vary slightly depending on your dish:

Storing Leftover Crisp

• Refrigerate: cover the cooled crisp and store it in the fridge for up to 3 days.
• Reheating: warm individual portions in a 350°F oven for 10 minutes to bring back some crunch. A microwave works in a pinch, but the topping will soften.
• Serve cold: you can eat it straight from the fridge, though the texture is much softer and the flavors are less bright.

Frequently Asked Questions

Can I assemble the crisp the night before?

Yes. Prepare the fruit filling and the topping, then store them separately in the refrigerator. Assemble and bake the next day when you are ready.

Why is my filling runny?

The cornstarch needs to reach a full boil inside the oven to thicken properly. Make sure the fruit bubbles for at least 15 minutes and then let the crisp rest for 10 minutes out of the oven.

My crumble topping sank into the fruit. What happened?

This usually happens if the butter was melted or too soft, or if you overworked the topping into a paste. Cold butter and a light touch keep the clusters separate.

Can I double this recipe?

Absolutely. Use a 9 by 13-inch pan and bake for 45 to 55 minutes, until the topping is deeply golden and the filling is thick and bubbly.

Can I make this with only rhubarb?

You can, but the filling will be quite tart. Increase the granulated sugar to 1 cup and expect a sharper, more bracing dessert.

Strawberry Rhubarb Crisp Recipe

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Prep Time 15 minutes mins

Cook Time 40 minutes mins

Total Time 55 minutes mins

Servings: 6 servings

Calories: 320

Ingredients Method Notes

Ingredients

  

• 1 lb fresh rhubarb, sliced 1/2 inch thick
• 1 lb fresh strawberries, hulled and quartered
• 3/4 cup granulated sugar
• 1/4 cup cornstarch
• 1 tablespoon lemon juice
• 1 teaspoon vanilla extract
• 1/2 teaspoon salt, divided
• 1 cup old-fashioned rolled oats
• 3/4 cup all-purpose flour
• 1/2 cup packed light brown sugar
• 1/2 teaspoon ground cinnamon
• 1/2 cup unsalted butter, cold and cut into small cubes

Method

 

1. Toss the rhubarb, strawberries, granulated sugar, cornstarch, lemon juice, vanilla, and half the salt in a large bowl. Let the fruit sit for 10 minutes while you preheat the oven to 375°F (190°C).
2. Stir together the oats, flour, brown sugar, cinnamon, and remaining salt in another bowl. Work the cold butter into the dry mix with your fingertips until it is crumbly with some pea-sized butter pieces, about 2 to 3 minutes.
3. Scrape the fruit and juices into a 9-inch square baking dish. Squeeze handfuls of the topping, break them into craggy pieces over the fruit, and cover it without packing down.
4. Place the dish on a baking sheet and bake for 35 to 40 minutes, until the topping is golden and the fruit bubbles thickly around the edges.
5. Rest the crisp on a wire rack for 10 minutes, then spoon it into bowls and serve warm.

Notes

Let the crisp cool for at least 10 minutes before serving so the filling sets. The topping is crispiest on the day it is made, but leftovers reheat nicely in a 350°F oven for 10 minutes.