If summer had a signature dessert, this Blueberry Rhubarb Crisp would be it. The bright, tart rhubarb pairs beautifully with sweet blueberries, and the crunchy oat-and-almond topping adds the perfect contrast. I love working with rhubarb and this version, using blueberries instead of the more common strawberries, is one of my favorites.
If you enjoy crisps, try other seasonal pairings like Peach Pecan Crisp or Strawberry Rhubarb Crisp—there are so many summer fruits that become outstanding when finished with oats, butter, and a touch of brown sugar.
Ingredients
The fruit is the star of this recipe, but the topping is where texture and depth come in. I prefer slivered almonds because they stay pleasantly crunchy after baking, though chopped walnuts or pecans also work well. Use rolled oats for a tender, rustic crumble.
What you need:
- Blueberries
- Rhubarb
- Lemon (zest and juice)
- Granulated sugar
- Cornstarch
- Rolled oats
- Light brown sugar
- Cinnamon
- Ginger
- Kosher salt
- Unsalted butter
- Slivered almonds
- Vanilla ice cream (for serving)
See the recipe card below for precise measurements and full instructions.
Use the recipe section below to jump straight to the full ingredient list, measurements, and step-by-step instructions.
Method
Preheat the oven to 375°F. Butter a 12–13 inch cast-iron skillet or a 9×13 baking dish. In a large bowl, toss the blueberries and sliced rhubarb with the granulated sugar, lemon zest, lemon juice, and cornstarch until the fruit is evenly coated. Transfer the fruit mixture to your prepared pan. A cast-iron skillet is my go-to because it keeps the filling hot and bubbly, but a baking dish works just as well.
In the same mixing bowl, make the crisp topping: combine the rolled oats, light brown sugar, ground cinnamon, ground ginger, kosher salt, room-temperature butter, and slivered almonds. Use your hands or a pastry cutter to work the butter into the dry ingredients until the mixture resembles coarse, moist crumbs. Crumble the topping evenly over the fruit.
Bake until the topping is deep golden brown and the fruit bubbles at the edges, about 60–75 minutes. It’s important the filling reaches a gentle boil so the cornstarch can thicken the juices. Let the crisp rest for about 10 minutes before serving so it sets slightly.
For a showstopper finish, serve warm straight from the oven topped with extra fresh blueberries and generous scoops of vanilla ice cream.
Notes & Tips
Rhubarb brings a pleasant sharpness, but the lemon is still important to round out and brighten the fruit flavors. If you prefer a sweeter filling, increase the granulated sugar when tossing it with the fruit, but I like to keep the sweetness moderate to showcase the rhubarb’s tang.
I bake this crisp in a large skillet because it browns nicely and holds heat, but a 9×13 baking dish works perfectly. If you want fewer dishes, toss the fruit in one bowl and then scrape the juices into the pan, making the topping in that same bowl.
Substitutions
Fresh or frozen blueberries and rhubarb both work; frozen can be used straight from the freezer, though baking time may be slightly longer. This recipe can be adapted to be dairy-free by swapping butter for coconut oil or a vegan butter; because a crisp relies on fat to bind the topping, the exact choice is flexible.
For a gluten-free version, confirm your oats and cornstarch are certified gluten-free. Light or dark brown sugar may be used—dark brown adds a deeper, molasses-like flavor. The cinnamon and ginger add subtle warmth; add a pinch of fresh nutmeg if you like a little extra spice. If nuts are an issue, omit the almonds, though they do add a lovely crunch.
📖 Recipe
Blueberry Rhubarb Crisp
Yield: about 8 cups
Prep Time: 10 minutes Cook Time: 1 hour Total Time: 1 hour 10 minutes
If summer were a dessert, this Blueberry Rhubarb Crisp would be it—perfectly sweet, tart, and topped with a crunchy oat-almond crumble.
Ingredients
- 1 pound fresh blueberries, plus more for garnish if desired
- 2 pounds fresh rhubarb, sliced diagonally
- 1 large lemon, zested and juiced
- 1 cup granulated sugar
- ½ cup cornstarch
- 2 cups rolled oats
- 1 cup light brown sugar, packed
- 1 teaspoon ground cinnamon
- 1 teaspoon ground ginger
- ½ teaspoon kosher salt
- 12 tablespoons unsalted butter, room temperature
- 1 cup slivered almonds
- Vanilla ice cream, for serving
Instructions
- Preheat the oven to 375°F and butter a 12–13 inch cast-iron skillet or a 9×13 baking dish.
- In a large bowl, combine the blueberries, rhubarb, lemon zest and juice, granulated sugar, and cornstarch. Stir until the fruit is evenly coated.
- Place the fruit mixture into the prepared pan.
- In the same bowl, combine the oats, brown sugar, cinnamon, ginger, salt, butter, and almonds. Use your hands to work the butter in until the mixture resembles wet sand.
- Spread the topping over the fruit and bake 60–75 minutes, until the top is dark golden and the fruit is bubbling at the edges. Ensure the filling comes to a boil so it thickens properly.
- Remove from the oven and let rest 10 minutes before serving.
- Scoop into bowls and top with vanilla ice cream. Leftovers can be refrigerated up to 3 days and reheated gently.
Nutrition (per serving, estimated)
Calories: 487 · Total Fat: 22g · Saturated Fat: 10g · Carbohydrates: 71g · Fiber: 6g · Protein: 6g · Sugar: 47g · Sodium: 87mg
Did you make this recipe? Leave a comment or a review and tell me how it turned out. I love seeing photos of your variations and tweaks!