Gluten-Free Rhubarb Crisp (Best Crumble Topping)

Enjoy a classic, old fashioned dessert with this easy gluten-free dessert recipe! Gluten-free rhubarb crisp has a juicy strawberry rhubarb filling topped with a thick, buttery oat crumble topping. Enjoy a no-fail recipe that teaches you how to make rhubarb crisp, step-by-step, along with modifications for dairy-free, using frozen fruit, making it without oats and many more gluten-free baking tips!

Easy Gluten-Free Rhubarb Crisp

There is no treat in the spring or summer like a gluten-free strawberry rhubarb crisp! While rhubarb is technically a vegetable, it pairs perfectly with the juicy sweetness of strawberries. If you are looking for a rhubarb only crumble, you can also enjoy it without the addition of strawberries!

For those in need of gluten-free dessert recipes, making a homemade fruit crisp is an ideal option. It utilizes simple, affordable and readily-available ingredients and even novice bakers can pull off this recipe with ease.

Plus, this gluten-free recipe for rhubarb crisp utilizes some easy tricks, to make an extra juicy filling with thick, buttery oat topping, similar to those used in gluten-free apple crisp and gluten-free peach crisp. There is a perfect balance between the strawberries’ sweetness and the rhubarb’s tartness, combining with the sweet and salty crumble topping.

Below I will teach you not only how to make gluten-free rhubarb crisp, but tricks for using frozen fruit, making a crisp without strawberries, dairy-free modifications, and many storing, freezing, and reheating tips. Let’s do this!

Ingredient Notes

Crisps are made up of two components, the fruit layer, tossed with a little sugar and cornstarch, and the oatmeal crumble on top. If you prefer a gluten-free crisp topping without oats, see the linked recipe to make an easy gluten-free rhubarb crisp without oats.

The crisp topping uses basic kitchen ingredients for an old fashioned flavor that really shines through. If you would like to elevate the spice, add a dash of cinnamon, nutmeg, or cardamom to the crumble mixture.

Strawberry Rhubarb Filling: 

• Rhubarb – You will need 1 pound of fresh rhubarb, which is about 12 medium stalks. To prep rhubarb, cut off the leaves and end where it was pulled from the ground. Cut the stalks, similar to celery, in ½-inch thick pieces. You may also use frozen, chopped rhubarb without having to thaw it first.
• Strawberries – Adds the perfect balance to the rhubarb’s tartness. Don’t be tempted to add additional strawberries because they release a lot of moisture during baking, which will make your crisp runny.
• Sugar – The amount of sugar is for the combination of rhubarb with strawberries. If you would like to enjoy a rhubarb only crisp, increase the rhubarb to 6 cups and sugar to 2/3 cup.
• Cornstarch – A naturally gluten-free thickener, alternatively substitute tapioca starch or gluten-free flour as well

Oat Crumble Topping: 

• Old-fashioned rolled oats – Oatmeal in pure form are gluten-free, but may become contaminated during packaging on shared equipment. Therefore, using certified gluten-free oats are best.
• All purpose gluten-free flour blend – I use and recommend Cup4Cup gluten-free flour for best results. Instead of gluten-free flour, oat flour or coconut flour may also be used.
• Sugar – A combination of granulated sugar and brown sugar builds structure and adds caramel flavors. If preferred, coconut sugar may also be used.
• Butter – For a dairy-free or vegan crisp, replace with softened plant-based vegan butter
• Pecans – Adds a salty crunch, but they can be omitted for a nut-free dessert. Chopped walnuts or almonds may also be used.

how to make Gluten-Free Rhubarb Crisp

Easy gluten-free strawberry rhubarb crisp comes together in minutes using a food processor. If you don’t have a fruit processor, see below for directions on making by hand.

Either fresh or frozen fruit may be used, but baking time will increase slightly if using frozen rhubarb or strawberries. You will also need to add an extra tablespoon of cornstarch to the filling.

(Below shows step-by-step photos and modified instructions. For the complete recipe, along with ingredient amounts, scroll down to the recipe card.)

1. To begin, preheat the oven to 350ºF. You will need a 2-quart baking dish, such as a 11X7-inch or 8X8-inch baking dish. If the crisp ingredients come to the top of your baking dish, you may want to set it on a foil-lined sheet pan to catch any drips bubbling over.
2. Begin by making the strawberry rhubarb fruit mixture so it has time to sit while you make the crisp topping, giving time for the juices to release. In a large bowl, gently toss together the chopped fruit, sugar, cornstarch, and vanilla extract. Set aside.
3. For the crumble, in a food processor, place 3/4 cup oats, gluten-free flour, brown sugar, vanilla, water, and salt. Pulse briefly to combine. (If you don’t have a food processor, please see instructions below on how to make the topping by hand.)
4. Next, add the butter and half of the pecans to your crisp mixture. Process until all of the ingredients come together in a large, crumbly ball. If necessary, stop halfway through processing to scrape the ingredients down the side of the bowl. Add the remaining pecans and 1/3 cup of oats. Pulse 2 to 3 times to combine these ingredients.
5. Add the fruit to the baking pan. Break off the crisp mixture into clumps and scatter it over the top of the fruit filling. Bake for 45-50 minutes, or until the juices are bubbling and the top is golden brown. Let the crisp cool for 30 minutes to thicken and then serve with either vanilla ice cream or a dollop of whipped cream.

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step-by-step web story instructions for this recipe!

Making a Rhubarb Crisp without strawberries

If you would like to enjoy a rhubarb only crisp, omit the strawberries from the recipe and increase the amount of rhubarb to 6 cups or 1 1/2 pounds.

Since rhubarb is more tart, and you won’t have the addition of sweeter strawberries, you may want to increase the sugar up to 2/3 cup. If you prefer a less sweet dessert, leave the sugar at 1/3 cup.

Using Frozen Rhubarb

You may also use frozen, chopped rhubarb without having to thaw it first. For the recipe, you will need 4 cups. The baking time will increase about 15 minutes. If the top is becoming too browned before the fruit bubbles, loosely tent with foil.

If you are using a combination of frozen rhubarb and frozen strawberries, I suggest adding an additional 1 tablespoon cornstarch to the fruit mixture.

Making crisp without a food processor

Homemade crisp may still be enjoyed by replacing some of the oats with homemade oat flour, coconut flour, or blanched almond flour,  and mixing by hand.

Stir together 1/2 cup oat, coconut, or almond flour with gluten-free flour, brown sugar, sugar, salt, 1/3 cup old fashioned oats, and optional chopped nuts. Then use a pastry blender or fork to mix in the vanilla extract, water, and softened butter

Dairy-Free Modification

Butter is the only ingredient in rhubarb crisp which contains dairy. Therefore, substituting with a vegan, plant based butter stick works great.

Also be sure your gluten-free flour does not contain milk powder. My recommended brand, Cup4Cup, does contain dairy. Therefore I would substitute King Arthur Measure-for-Measure or use an alternative flour, such as oat flour or almond flour.

Storing and reheating

Store the crisp on the counter, covered with foil, at room temperature for 1 to 2 days. Avoid using plastic wrap, which traps moisture, making the topping soggy.

If you would like to keep your gluten-free rhubarb crumble for longer than 2 days, store it in your refrigerator, in an airtight container, for up to one week.

When you are ready to reheat, bring it out of the refrigerator and let it come to room temperature. Place it in your oven at 300ºF for about 20 minutes, or until heated through. You may need to cover with foil if the topping starts to get too brown.

How to Freeze and Reheat

To freeze, first bake and allow to cool completely. Then, wrap the cooled dessert tightly in plastic wrap, cover in foil, and freeze for up to three months.

To reheat, thaw it either on the counter, or in the fridge overnight and then bake at 350ºF for 30 minutes, or until heated through.

It may also be frozen unbaked for a make-ahead dessert. Bake directly from frozen, adding about an additional 20 minutes. If the top is becoming overly browned before the fruit is thickened and heated through, loosely tent foil over the top.

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