If you don't have a cast iron skillet, you can also use an 8x8 baking pan, or a 9x9 baking pan. Skip the step where you heat the pan on the stovetop, and instead cook the filling an additional 5 to 10 minutes before transferring to the baking pan and adding the crisp topping.
For the topping:
- 1 1/2 cups (190 g) rolled oats
- 1 cup (140 g) all-purpose flour
- 1/2 cup (110 g) packed dark brown sugar
- 1/2 cup (100 g) white granulated sugar
- 1/2 teaspoon ground cinnamon
- 1/4 teaspoon kosher salt
- 12 tablespoons (175 g or 1 1/2 sticks) unsalted butter, melted and cooled
For the filling:
- 4 cups (620 g) strawberries, stemmed, hulled and, cut in half if large
- 3/4 cup (250 g) white granulated sugar, divided
- 1 tablespoon chopped candied ginger
- 2 tablespoon cornstarch
- Zest from 1 medium orange
- 4 cups (500 g or a little bit over 1 pound) sliced rhubarb (1-inch chunks) from about 5 to 6 thick stalks or 10 to 12 skinny stalks
- Vanilla ice cream, store-bought or homemade
1 Preheat the oven to 350°F.
2 Make the topping: Combine the oats, flour, both sugars, cinnamon, and salt in a medium-sized bowl. Mix with a balloon whisk until consistent in color and all the ingredients are evenly distributed. Use your fingers to break up any chunks of brown sugar.
Drizzle the melted butter over the dry ingredients, tossing with a fork until the topping starts to clump together and the dry ingredients are moist. Place the bowl in the refrigerator to chill while you prepare the fruit.
3 Macerate the strawberries: Combine the strawberries, 1/2 cup of the sugar, candied ginger, cornstarch and orange zest in a large bowl, tossing to make sure the strawberries are coated with the dry ingredients. Set aside.
4 Cook the rhubarb: Spray a 10-inch cast iron skillet with cooking oil, and add the rhubarb and the remaining 1/4 cup of sugar. Cook over medium-high heat, stirring constantly, for 5 to 7 minutes, or until the sugar has dissolved and the rhubarb juice starts to thicken. You want to cook off some of the liquid, but you don’t want the rhubarb to get mushy or break down.
5 Add the strawberries and bake in the oven: Add the strawberry mixture to the hot pan with the rhubarb, covering the rhubarb evenly. Bake in the oven for 30 to 35 minutes.
6 Add the topping and continue baking: Take the pan out of the oven and sprinkle the crisp topping over the fruit filling. Return to the oven for an additional 15 to 20 minutes, or until the top of the crisp is golden brown and the fruit filling is bubbling hot.
7 Cool and serve: Let the crisp cool at least 15 to 20 minutes before serving, to allow the filling to thicken a bit. Serve with your favorite vanilla ice cream.
This crisp is best eaten the same day but you can store it in the fridge after it has completely cooled, covered with plastic wrap, for up to 2 days (the crisp topping will soften, but still be delicious). Warm up in a 350°F oven for 10 to 15 minutes before serving.