Rhubarb Crisp Recipe
Rhubarb refers to the fleshy, edible stalks (petioles) of Rheum species and hybrids (culinary rhubarb), which are cooked and eaten. Although rhubarb is a vegetable, it is frequently used in the same way as fruits.
Rhubarb appears to divide people into two camps: those who adore it and those who despise it, but I assume the detractors were previously traumatized by a dish of overcooked rhubarb mush. Even when cooked precisely, rhubarb’s high amounts of oxalic acid may produce a tooth-coating chalkiness that leaves an unpleasant taste in anyone’s mouth.
Oxalic acid is the same culprit behind the dreaded sensation of “spinach teeth” (spinach teeth is a gritty, fuzzy, or chalky sensation on your teeth) after eating salad, and it exists at toxic levels in rhubarb leaves, so be sure to toss those out! The high but tolerable level in the rhubarb itself leads some bakers to bury their rhubarb in sugar, which makes for a painfully sweet/tart concoction.
With all of those drawbacks, it’s no surprise that some people are wary of (or openly antagonistic to) rhubarb, but thankfully, all of those issues can be remedied with science and, maybe, a splash of flair when it comes to seasoning. And what about those of us who are already rhubarb fans? These tips will propel your enthusiasm to new heights.
Making the streusel topping, which is what makes a crisp a crisp, is the first step. Streusels are far more customizable than pie crust, which makes switching between recipes simple. There is a specific combination I love to pair with rhubarb.
It contains rolled oats, whole wheat flour, brown sugar, cinnamon, and Chinese five-spice powder. Additionally, a lot of butter was added to the generally lean fruit filling to enhance it.
If you don’t have whole wheat flour on hand, all-purpose flour will work just as well. Whole wheat flour provides the topping with an extra-crispy texture, and it pairs well with brown sugar and cinnamon to taste like graham crackers. Simply pick out your preferred APF-style mix if you’re gluten-free.
When used with rhubarb, the perfume of anise seeds (together with the five-spice powder’s echoes of fennel and star anise) works wonders, bringing out more of its naturally herbaceous flavour without dominating its delicate flavour.
To make my rhubarb crispy, I begin by blending two ounces of an elderflower liqueur, such as St-Germain, with two-thirds of the rhubarb, sugar, and starch. Even though rhubarb contains 90% water, you can substitute water or an additional two ounces of fruit if you don’t have elderflower on hand. However, the elderflower’s delicate floral scent helps to bring out the nuances of rhubarb.
Place the mixture in a baking dish measuring 7 by 11 inches. (A nine-inch deep-dish pie pan will also work, but I like the rectangle form better since it provides more surface area for the streusel later.)
The dish should be securely covered in foil and baked until moist. The time required for this in a 400°F (200°C) oven varies considerably depending on the size and composition of your baking dish, so if you’re using a metal dish, check on the fruit a little earlier.
Pull the rhubarb out of the oven after it has released its juices, then, using a heat-resistant spatula, whisk in 1/4 teaspoon of baking soda. The acidity of the rhubarb isn’t completely neutralized, but this method softens its edges. This is especially useful when working with hothouse rhubarb, which has a sourer flavour.
Keep stirring until the effervescence subsides to ensure that there is no pocket of baking soda left inactive. Next, over the remaining rhubarb pour the syrupy rhubarb. After gently mixing, return the mixture to the baking dish.
By baking the crisp in stages, several textures are created, including large chunks of harder fruit and creamy morsels of rhubarb that melt into a gooey filling. Add the prepared streusel on top, squeezing out a thin sheet from each handful.
Once everything is coated, put the pan back in the oven and bake for another 30 minutes, or until the centre is sizzling hot. Let this be your cue rather than sticking to a rigid deadline because if it’s not sizzling hot, the filling won’t thicken as it should.
Before serving, allow the completed crisp to cool for at least 30 minutes because it will first be soupy and quite hot.
For the Topping:
- 140g (about 2/3 cup) of light brown sugar
- 105g (3/4 cup) of whole wheat flour
- 115g (1 1/3 cups) old-fashioned rolled oats
- 1 ½ teaspoon ground cinnamon
- 1 teaspoon whole anise seeds (optional)
- 1 teaspoon Chinese five-spice powder
- 1/4 teaspoon salt
- 140g unsalted butter, soft but cool, about 68°F (20°C)
- 1 cup raw pecan pieces
For the Filling:
- 11 cups rhubarb, cut into 3/4-inch pieces from around eighteen 24-inch stalks
- 300g sugar
- 2/3 cup of tapioca flour
- 1/4 cup elderflower liqueur or water
- 3/4 teaspoon salt
- 1/4 teaspoon baking soda
To Serve (optional):
- Strawberry whipped cream
- In a stand mixer bowl with a paddle attachment, combine brown sugar, whole wheat flour, rolled oats, cinnamon, anise seed (if using), five-spice powder, salt, and butter. For around 5 minutes, combine at moderate speed to create a thick dough. As an alternative, this can be carried out manually. Pecans can be added, then transferred to a zip-top bag and stored in the fridge for up to a month until needed.
- For the Filling: Set the oven rack in the lower-middle position and heat the oven to 400°F (200°C). Use a flexible spatula to combine half of the prepared rhubarb (about 5 1/2 cups), sugar, tapioca flour, elderflower liqueur or water, and salt in the same bowl from the stand mixer (do not wash). The mixture will be quite dry. Any leftover sugar or starch should be sprinkled on top before being transferred to a 7 by 11-inch baking dish or a 9-inch deep-dish pie pan. The dish should then be covered with foil. Bake the rhubarb for approximately 30 minutes, until it is wilted and juicy, on a half-sheet pan coated with foil or parchment. Meanwhile, add the remaining fruit to the same bowl.
- Take the baking dish out of the oven, remove the foil, and sprinkle with baking soda. With a heat-resistant spatula, gently stir until the fluids begin to bubble. Return to the baking dish after folding in the remaining rhubarb. Top with streusel, flattening each addition into a thin layer for equal covering. Bake until the crisp is bubbling in the centre.
- Allow at least 30 minutes to cool before serving, since the filling will be quite hot and runny at first. As it cools to room temperature, the crisp will thicken. Serve à la mode or with globs of strawberry or brown sugar whipped cream if desired. Wrapped in foil, the crisp will keep at room temperature for 3 days.