
Crisps are one of my favorite ways to use up fresh or frozen fruit, and this gluten-free rhubarb crisp is a knockout winner! It literally has every texture and flavor you could want in a dessert—soft baked rhubarb, crunchy oat topping, tartness, sweetness, and a hint of spice and salt. What more do you need?
We are not a gluten-free household, however, we have gluten-intolerant family members. I also like the flavor of buckwheat flour so I always have it on hand and bake with it often (two of my faves are these double chocolate buckwheat brownies or this buckwheat banana bread).
If you have frozen rhubarb in your freezer, get ready to enjoy this delicious and simple dessert year-round!
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💞 Why You’ll Love This Recipe
✔️ It really showcases the beauty of fresh spring rhubarb.
✔️ It’s so simple, anyone can make it.
✔️ You can use fresh or frozen rhubarb!
📋 Ingredients

Ingredient Notes
- Rhubarb—You can use fresh or frozen chopped rhubarb.
- Buckwheat Flour—Gluten and grain free, look for finely milled buckwheat flour that’s almost grey in color.
- Rolled Oats—This is not the same thing as instant or quick oats.
It’s important to note that when making substitutions in recipes, the texture and flavor may be slightly different. However, these substitutes are the best options if you are looking to change the original recipe.
Ingredient Substitutions
- Sugar—I sometimes substitute lavender sugar for half of the sugar called for.
- Oats—Quick oats can be substituted for rolled oats but won’t have the same texture.
- Buckwheat Flour—I have substituted brown rice flour for buckwheat flour with great results.
- Lemon Juice—If you don’t have fresh lemon juice use bottled.
- Cornstarch—Arrowroot powder or tapioca starch are good substitutes.
Use the JUMP TO RECIPE button at the top of this post, or scroll to the bottom of the post, to see the PRINTABLE recipe card with ingredient measurements and complete instructions.
👩🍳 How To Make Gluten-Free Rhubarb Crisp
STEP 1—Stir together the chopped rhubarb and lemon juice. Mix together the sugar and cornstarch in a smaller bowl. Sprinkle the mixture over the rhubarb. Stir and set aside.
STEP 2—Combine the topping ingredients in a second bowl. Mix with your hands to combine then add the butter. Rub together until all butter is incorporated and no bits of dry flour remain.

STEP 3—Pour the rhubarb into a greased baking tin. Spread the rhubarb out in an even layer.
STEP 4—Top with the oat mixture then bake for 40 to 45 minutes, or until the top is golden. Cool on a wire rack for 15 minutes before serving warm, with ice cream or whipped cream.
📝 Recipe Notes
- Wash rhubarb well before chopping.
- To use frozen rhubarb, there’s no need to thaw it first. Simply proceed with the recipe as written.
- If your stalks of rhubarb are huge, slice them in half lengthwise before chopping them into chunks.
- I mix the sugar and cornstarch in a small bowl before adding them to the rhubarb. This method ensures an even, lump-free coating, however, add them straight to the rhubarb without pre-mixing if you want.
- Let the fruit bubble in the oven for a minimum of five minutes to help ensure a properly thickened filling.

🙋♀️ Recipe FAQ
No. the only reason to peel rhubarb is if the stalks are old or woody, similar to mature asparagus. Spring and early summer rhubarb doesn’t usually need to be peeled.
For small or medium stalks of rhubarb, trim both ends then slice the stalks into ½-inch (1-¼ cm) chunks. For larger stalks of rhubarb, trim the ends and slice the stalks down the middle lengthwise before chopping.
You probably haven’t let the crisp bake long enough. Let the fruit bubble for a minimum of five minutes before removing the crisp from the oven.
Did you make this gluten-free rhubarb crisp? Please rate the recipe and tell me how it went in the comments below. Also, stay in touch with me on Instagram, Facebook, and Pinterest to see more delicious food and recipes!
🖨 Recipe

Gluten-Free Rhubarb Crisp
Equipment
- 1 8-inch (20-cm) square or round baking dish glass or metal
- Measuring cups and spoons or digital kitchen scale
- 2 Large mixing bowls
- Rubber spatula or wooden spoon
- Wire cooling rack
Ingredients
For The Rhubarb Filling
- 4 cups rhubarb, washed, chopped into ½ inch (1 ¼ cm) chunks
- 2 teaspoons lemon juice
- ½ cup sugar
- ¼ cup cornstarch
For The Buckwheat Oat Topping
- ½ cup buckwheat flour
- ½ cup brown sugar, tightly packed
- ½ cup rolled oats , also called large flake oats
- 1 teaspoon cinnamon, ground
- ⅛ teaspoon salt
- ½ cup butter, room temperature
Instructions
- Preheat the oven to 350ºF (180ºC). Lightly grease an 8-inch (20-cm) square or round baking dish with butter.
- In a large bowl, stir together the chopped rhubarb and lemon juice.
- Mix together the sugar and cornstarch in a smaller bowl. Sprinkle the mixture over the rhubarb. Stir well to combine then set aside.
- In a second larger bowl, combine the buckwheat flour, brown sugar, oats, cinnamon, and salt. Mix everything together with your hands, breaking up large chunks of brown sugar by rubbing them together with your fingers.
- Add the butter to the oat mixture. Again with your hands, rub the butter into the oats. The topping is ready when all of the butter has been incorporated, and no dry bits of buckwheat flour remain in the bottom of the bowl.
- Give the rhubarb a good stir then pour it into the prepared baking tin. Spread the rhubarb out into an even layer, then top it all over with the buckwheat mixture. Place the crisp in the oven and bake it for 40 to 45 minutes, or until the top is golden and the rhubarb is bubbling for at least five minutes. Cool the crisp on wire rack for 15 minutes before serving warm with ice cream or whipped cream.
Notes
- Wash rhubarb well before chopping.
- To use frozen rhubarb, there’s no need to thaw first. Simply proceed with the recipe as written.
- If your stalks of rhubarb are huge, slice them in half lengthwise before chopping into chunks.
- I mix the sugar and cornstarch in a small bowl before adding them to the rhubarb. This method ensures an even, lump-free coating, however, add them straight to the rhubarb without pre-mixing if you want.
- Let the fruit bubble in the oven for a minimum of five minutes to help ensure a properly thickened filling.
Colleen says
I have tons of rhubarb and I am gluten-free, so always have buckwheat flour. This looks so simple & delicious, perfect for a summer dessert.
Jess says
I absolutely love rhubarb and I’m loving the simplicity of this recipe! So perfect for the summertime!
Cynthia @ Cynful Kitchen says
We always get tonnes of rhubarb every year and I don’t always feel like making pie crust. This crisp recipe is great! Great tips on freezing rhubarb. Thank you.
NANCY @instanomss says
running out to get some rhubarbs now!!
Julia says
What a fantastic looking crisp. A perfect way to use up seasonal rhubarb. I love how simple this recipe is as well I’m sure it’s delicious. And it¡s gluten free! Thanks for sharing.