When you want a classic early-summer dessert that balances sweet and tart, a Strawberry Rhubarb Crisp is as timeless as it gets. Sweet, juicy strawberries perfectly complement the sharp, punchy tang of fresh rhubarb under a golden, buttery brown sugar oat topping that bakes up delightfully crunchy.
The secret to a fruit crisp that thickening properly without becoming soupy is Using Cornstarch or Tapioca and Slicing Rhubarb Thinly. Rhubarb releases a lot of moisture as it bakes; tossing the fruit with just enough starch absorbs those juices into a thick, jammy fruit sauce that coats every spoonful.
Why You’ll Love This Crisp
- The Ultimate Sweet-Tart Balance: Juicy sweet strawberries cut right through the bright acidity of stalky rhubarb.
- Crunchy Oat Streusel: Rolled oats, brown sugar, and cold butter bake into a crispy, golden crown.
- Warm & Comforting: Best served piping hot straight out of the oven with a scoop of cold vanilla ice cream.
- Uses Fresh or Frozen Fruit: Works beautifully with fresh spring produce or thawed frozen fruit year-round.
Key Ingredients Overview
- Fresh Rhubarb & Strawberries: Sliced into bite-sized pieces for an even fruit ratio.
- Cornstarch & Lemon Juice: Thickens the fruit juices into a glossy filling and enhances acidity.
- Rolled Oats & All-Purpose Flour: Forms the foundation of the crunchy streusel topping.
- Brown Sugar & Cold Butter: Sweetens the topping and creates buttery, clumped golden clusters as it bakes.
Step-by-Step Instructions
1.The Fruit Filling Toss:5 min.
Preheat your oven to $180^\circ\text{C}$ ($350^\circ\text{F}$) and grease an 8×8-inch baking dish (or 9-inch pie dish). In a large bowl, toss 3 cups chopped fresh rhubarb (½-inch pieces), 3 cups hulled and quartered strawberries, ⅓ cup granulated sugar, 3 tablespoons cornstarch, and 1 tablespoon lemon juice until the fruit is evenly coated. Transfer to the prepared dish.
2.The Golden Streusel Topping:5 min.
In a separate bowl, combine 1 cup rolled oats, ½ cup all-purpose flour, ½ cup packed light brown sugar, ½ teaspoon ground cinnamon, and ¼ teaspoon salt. Add ½ cup (1 stick) cold unsalted butter cut into small cubes.
3.The Clump & Cover:3 min.
Use your fingertips or a pastry cutter to rub the cold butter into the dry oat mixture until large, buttery clumps form. Scatter the streusel evenly over the strawberry-rhubarb filling, squeezing a few extra clumps in your hands for crunch.
4.The Golden Bake:45 min.
Bake at $180^\circ\text{C}$ ($350^\circ\text{F}$) for 40 to 45 minutes until the oat topping is deep golden brown and the fruit filling is thick and bubbling vigorously around the edges.
5.The Rest & Vanilla Scoop:10 min.
Remove from the oven and let cool for 10 to 15 minutes to allow the fruit juices to thicken up. Spoon into bowls warm, top with a large scoop of vanilla bean ice cream, and enjoy!

Expert Tips for Success
- Look for Vigorous Bubbling: To ensure the cornstarch activates and thickens the fruit filling, make sure you see active bubbling in the center of the dish before pulling it from the oven!
- Cold Butter is Essential: Using melted butter makes streusel greasy and heavy. Using cold, cubed butter rubbed into oats creates light, crispy, distinct topping clusters.
- Adjust Sugar to Taste: Rhubarb harvested early in the season can be extremely tart! Taste a piece of rhubarb beforehand; if it’s very sharp, add an extra 2 tablespoons of sugar to the filling.
The Recipe Card
- Prep Time: 15 mins
- Bake Time: 45 mins
- Total Time: 1 hour
- Yield: 6 Servings
Ingredients:
- The Fruit Filling: 3 cups Rhubarb (chopped), 3 cups Fresh Strawberries (quartered), ⅓ cup Granulated Sugar, 3 tbsp Cornstarch, 1 tbsp Lemon Juice.
- The Oat Streusel Topping: 1 cup Rolled Oats, ½ cup All-Purpose Flour, ½ cup Light Brown Sugar (packed), ½ tsp Ground Cinnamon, ¼ tsp Salt, ½ cup (1 stick) Unsalted Butter (cold, cubed).
Instructions:
Toss rhubarb, strawberries, granulated sugar, cornstarch, and lemon juice; transfer to a greased 8×8-inch dish. Rub cold butter into oats, flour, brown sugar, cinnamon, and salt until clumpy. Spread streusel over fruit. Bake at $180^\circ\text{C}$ ($350^\circ\text{F}$) for 40–45 minutes until bubbling and golden. Rest 10 minutes and serve warm with ice cream.