Why It Works
- Whole wheat flour gives the streusel a graham cracker–like flavor.
- Anise seed and Chinese five-spice powder complement rhubarb, coaxing out more of its natural aroma.
- Tapioca starch forms a light, clear gel that keeps the filling gooey and thick, never gloppy.
- Elderflower heightens the aroma of strawberries and rhubarb alike.
- Baking in stages creates the ideal ratio of gooey filling and tender fruit.
- Baking soda mellows the sharp acidity of rhubarb.
This crisp is made just like our Rhubarb Crisp, but with strawberries standing in for a portion of the rhubarb. They give the crisp a sweeter profile and more complex flavor. Use the best berries you can find.
- For the Topping:
- 5 ounces light brown sugar (about 2/3 cup, packed; 140g)
- 3 3/4 ounces whole wheat flour (about 3/4 cup, spooned; 105g)
- 4 ounces old-fashioned rolled oats (about 1 1/3 cups; 115g)
- 1 1/2 teaspoons ground cinnamon
- 1 teaspoon whole anise seed (optional)
- 1 teaspoon Chinese five-spice powder
- 1/4 teaspoon (1g) Diamond Crystal kosher salt; for table salt, use half as much by volume or use the same weight
- 5 ounces unsalted butter (10 tablespoons; 140g), soft but cool, about 68°F (20°C)
- For the Filling:
- 2 pounds rhubarb, cut into 3/4-inch pieces (about 8 cups; 905g), from around twelve 24-inch stalks (34 ounces; 965g)
- 10 1/2 ounces sugar (about 1 1/2 cups; 300g)
- 2 1/2 ounces tapioca flour (about 2/3 cup; 75g), such as Bob’s Red Mill
- 2 ounces elderflower liqueur or water (1/4 cup; 55g)
- 3/4 teaspoon (3g) Diamond Crystal kosher salt; for table salt, use half as much by volume or use the same weight
- 12 ounces trimmed strawberries (about 2 cups; 340g), cut in half if large
- 1/4 teaspoon baking soda
- To Serve (optional):
- 1 recipe lemon or orange whipped cream
For the Topping: Combine brown sugar, whole wheat flour, rolled oats, cinnamon, anise seed (if using), five-spice powder, salt, and butter in the bowl of a stand mixer fitted with a paddle attachment. Mix on low speed to form a thick dough, about 5 minutes. Alternatively, this can be done by hand. Transfer to a zip-top bag and refrigerate until needed, up to 1 month.
For the Filling: Adjust oven rack to lower-middle position and preheat to 400°F (200°C). In the same bowl from the stand mixer (no need to wash), combine 22 ounces rhubarb (about 5 1/2 cups; 620g) with sugar, tapioca flour, elderflower liqueur or water, and salt. Toss with a flexible spatula and transfer to a 7- by 11-inch baking dish or 9-inch deep-dish pie pan, sprinkling any remaining sugar/starch on top. Cover with foil, place on a foil- or parchment-lined half-sheet pan, and bake until rhubarb is wilted and juicy, about 30 minutes. Meanwhile, transfer strawberries and remaining 10 ounces rhubarb (about 2 1/2 cups; 285g) to the same bowl.
To Finish: Remove baking dish from oven, discard foil, and sprinkle with baking soda. Stir carefully with a heat-resistant spatula until juices begin to fizz. Pour over remaining fruit and fold to combine, then return to baking dish. Top with handfuls of prepared streusel, flattening each addition into a thin sheet to achieve even coverage. Continue baking until crisp is bubbling in the very center, about 35 minutes more. (The time will vary dramatically depending on the exact dimensions and material of your baking dish.)
Cool at least 30 minutes before serving, as the filling will be dangerously hot and extremely runny at first. The crisp will thicken as it cools to room temperature. If you like, serve à la mode or with dollops of lemon or orange whipped cream. Wrapped in foil, the crisp will keep 3 days at room temperature.
Due to disparate sourcing practices, tapioca starch manufactured outside the US may be derived from sago, which has different gelling properties from true tapioca (cassava). Look for brands that mention cassava by name; my favorite is Bob's Red Mill, available in the baking aisle of most supermarkets or online.
Make-Ahead and Storage
Wrapped in foil, the crisp will keep 3 days at room temperature.