I didn’t grow up eating rhubarb, so when I first saw those pink and green stalks at the farmers market, I had no idea what to do with them. My neighbor kept raving about her grandmother’s rhubarb desserts, and I figured it was time to give it a try.
Turns out, rhubarb crumble is pretty forgiving—especially when you go gluten free. The tart rhubarb gets sweet and soft in the oven, and that buttery oat topping bakes up golden and crispy. Once I figured out the right gluten free flour blend, this became my go-to spring dessert. It’s the kind of recipe where you just layer everything in a pan and let the oven do the work.
Why You’ll Love This Rhubarb Crumble
- Naturally gluten-free friendly – Just swap in your favorite gluten-free flour blend, and you’ve got a dessert everyone at the table can enjoy without feeling left out.
- Quick and easy – This crumble comes together in under an hour, making it perfect for last-minute dinner parties or when you’re craving something sweet without spending all day in the kitchen.
- Simple ingredients – You probably have most of these pantry staples on hand already, so you can whip this up whenever the mood strikes.
- Perfect balance of tart and sweet – The tangy rhubarb filling paired with the buttery, cinnamon-spiced crumble topping creates that classic dessert combination that never gets old.
- Great for spring and summer – When rhubarb is in season, this is the perfect way to use it up, and it tastes amazing served warm with a scoop of vanilla ice cream.
What Kind of Rhubarb Should I Use?
Fresh rhubarb is always your best bet for this crumble, and you’ll find it at most grocery stores during spring and early summer. The color of the stalks can range from bright red to pale green, and while the red looks prettier, the green actually tastes just as good and works perfectly fine in this recipe. If fresh rhubarb isn’t available, frozen rhubarb is a solid backup option – just make sure to thaw it first and drain off any excess liquid so your crumble doesn’t get too watery. When prepping your rhubarb, trim off the leaves (they’re toxic!) and the dry ends, then cut the stalks into roughly 1-inch pieces for even cooking.
Options for Substitutions
This crumble is pretty forgiving when it comes to swaps, so here are some options if you need to make changes:
- Flour: Since this is a gluten-free recipe, make sure you’re using a gluten-free flour blend (like Bob’s Red Mill 1-to-1). Regular all-purpose flour won’t work if you need to keep it gluten-free. You can also try almond flour, though the texture will be a bit different.
- Rhubarb: If you can’t find fresh rhubarb, frozen works great – just thaw it first and drain any excess liquid. You can also mix in strawberries or apples (about 2 cups rhubarb and 2 cups of the other fruit) for a different flavor.
- Oats: Make sure to use certified gluten-free oats if you’re keeping this recipe gluten-free. You can substitute with more flour or crushed gluten-free cereal if needed.
- Butter: For a dairy-free version, use coconut oil or vegan butter. The crumble topping will be just as good.
- Egg: If you need an egg substitute, try a flax egg (1 tablespoon ground flaxseed mixed with 3 tablespoons water, let sit for 5 minutes) or use 1/4 cup applesauce.
- Sugar: You can reduce the sugar to 3/4 cup if your rhubarb is on the sweeter side, or swap white sugar for coconut sugar for a deeper flavor.
Watch Out for These Mistakes While Baking
The biggest mistake when making rhubarb crumble is not cutting the rhubarb into uniform pieces – aim for 1/2 to 1-inch chunks so everything cooks evenly and you don’t end up with some pieces that are mushy while others are still tough.
Another common error is skipping the step of letting the rhubarb mixture sit for a few minutes after combining, which helps draw out excess moisture and prevents a watery filling that can make your crumble topping soggy.
Make sure your butter is cold when mixing the topping – warm or melted butter will create a dense layer instead of those nice crumbly bits we’re looking for, so cut it into small cubes and work quickly.
Finally, don’t pull the crumble out too early just because the top looks golden – the filling needs time to bubble around the edges to ensure the rhubarb is fully tender and the juices have thickened properly.
What to Serve With Rhubarb Crumble?
A warm rhubarb crumble is absolutely perfect with a big scoop of vanilla ice cream on top – the cold ice cream melting into the warm, tart filling is really something special. You can also serve it with a dollop of fresh whipped cream or even some Greek yogurt if you want to balance out the sweetness a bit. This dessert is great for spring and summer gatherings, and I like to pair it with a cup of coffee or tea for an afternoon treat. If you’re serving it for a dinner party, consider putting out both ice cream and whipped cream so everyone can choose their favorite topping.
Storage Instructions
Store: Keep your rhubarb crumble covered with foil or plastic wrap in the fridge for up to 4 days. It actually tastes pretty great cold straight from the fridge for breakfast, or you can warm it up whenever you want that fresh-baked feel again.
Freeze: This crumble freezes really well for up to 3 months. You can freeze it before or after baking – just wrap it tightly in plastic wrap and then foil. If freezing unbaked, add about 15 extra minutes to the baking time when you’re ready to cook it.
Reheat: Warm individual portions in the microwave for about 30-45 seconds, or reheat the whole dish in a 350°F oven for 15-20 minutes until it’s heated through. The topping gets nice and crispy again in the oven, which is my favorite way to enjoy leftovers.
| Preparation Time | 10-15 minutes |
| Cooking Time | 35-40 minutes |
| Total Time | 45-55 minutes |
| Level of Difficulty | Easy |
| Servings | 8 servings |
Estimated Nutrition
Estimated nutrition for the whole recipe (without optional ingredients):
- Calories: 3850-4100
- Protein: 30-36 g
- Fat: 145-160 g
- Carbohydrates: 600-640 g
Ingredients
For the filling:
- 5 cups rhubarb (sliced into 1-inch pieces)
- 1 1/4 cups sugar
- 1 egg (large, room temperature)
- 2 tbsp gluten free flour (I always use Bob’s Red Mill 1-to-1)
- 1/2 tsp cinnamon
For the topping:
- 1 3/4 cups gluten free flour (I prefer King Arthur for the best texture)
- 1 cup brown sugar (firmly packed for better moisture)
- 1 cup oats
- 1/2 tsp cinnamon
- 1/4 tsp salt
- 1 cup butter (cold, cut into 1/2-inch cubes)
Step 1: Prepare the Mise en Place and Preheat
- 5 cups rhubarb
- 1 cup butter
Preheat your oven to 375°F and grease a 9×13 inch baking dish (or similar size) with butter or cooking spray.
While the oven heats, slice the rhubarb into 1-inch pieces and measure out all your ingredients.
I like to cut the cold butter into 1/2-inch cubes and keep it in the freezer until I’m ready to use it—this helps create the best crumbly texture in the topping.
Step 2: Prepare the Rhubarb Filling
- 5 cups rhubarb
- 1 1/4 cups sugar
- 1 egg
- 2 tbsp gluten free flour
- 1/2 tsp cinnamon
In a medium bowl, combine the sliced rhubarb with 1 1/4 cups sugar, 1 large egg (room temperature), 2 tablespoons gluten free flour, and 1/2 teaspoon cinnamon.
Stir gently until the rhubarb is evenly coated and the egg is fully incorporated.
The egg and flour will help thicken the filling as it bakes, creating a nice jammy consistency.
Step 3: Build the Crumble Topping
- 1 3/4 cups gluten free flour
- 1 cup brown sugar
- 1 cup oats
- 1/2 tsp cinnamon
- 1/4 tsp salt
- 1 cup butter
In a separate bowl, whisk together 1 3/4 cups gluten free flour, 1 cup firmly packed brown sugar, 1 cup oats, 1/2 teaspoon cinnamon, and 1/4 teaspoon salt.
Add the cold butter cubes and use a pastry cutter, fork, or your fingertips to work the butter into the dry mixture until it resembles coarse breadcrumbs with pea-sized pieces of butter still visible.
I prefer using my fingertips for better control—just work quickly so the butter stays cold and creates those lovely crumbly pockets.
Step 4: Assemble and Bake
- rhubarb filling from Step 2
- crumble topping from Step 3
Pour the rhubarb filling from Step 2 into the prepared baking dish, spreading it into an even layer.
Scatter the crumble topping from Step 3 evenly over the rhubarb, breaking up any large clumps with your fingers but leaving some texture.
Bake for 35 to 40 minutes until the topping is golden brown and the filling is bubbling around the edges.
The fruit should be tender when pierced with a fork.
Step 5: Cool and Serve
Remove the crumble from the oven and let it cool for at least 10 minutes before serving—this allows the filling to set slightly and makes it easier to scoop.
Serve warm with vanilla ice cream or whipped cream, or enjoy it cold the next day (the flavors actually deepen and the texture improves as it sits).
Easy Gluten Free Rhubarb Crumble
Ingredients
For the filling
- 5 cups rhubarb (sliced into 1-inch pieces)
- 1 1/4 cups sugar
- 1 egg (large, room temperature)
- 2 tbsp gluten free flour (I always use Bob's Red Mill 1-to-1)
- 1/2 tsp cinnamon
For the topping
- 1 3/4 cups gluten free flour (I prefer King Arthur for the best texture)
- 1 cup brown sugar (firmly packed for better moisture)
- 1 cup oats
- 1/2 tsp cinnamon
- 1/4 tsp salt
- 1 cup butter (cold, cut into 1/2-inch cubes)
Instructions
- Preheat your oven to 375°F and grease a 9x13 inch baking dish (or similar size) with butter or cooking spray. While the oven heats, slice the rhubarb into 1-inch pieces and measure out all your ingredients. I like to cut the cold butter into 1/2-inch cubes and keep it in the freezer until I'm ready to use it—this helps create the best crumbly texture in the topping.
- In a medium bowl, combine the sliced rhubarb with 1 1/4 cups sugar, 1 large egg (room temperature), 2 tablespoons gluten free flour, and 1/2 teaspoon cinnamon. Stir gently until the rhubarb is evenly coated and the egg is fully incorporated. The egg and flour will help thicken the filling as it bakes, creating a nice jammy consistency.
- In a separate bowl, whisk together 1 3/4 cups gluten free flour, 1 cup firmly packed brown sugar, 1 cup oats, 1/2 teaspoon cinnamon, and 1/4 teaspoon salt. Add the cold butter cubes and use a pastry cutter, fork, or your fingertips to work the butter into the dry mixture until it resembles coarse breadcrumbs with pea-sized pieces of butter still visible. I prefer using my fingertips for better control—just work quickly so the butter stays cold and creates those lovely crumbly pockets.
- Pour the rhubarb filling from Step 2 into the prepared baking dish, spreading it into an even layer. Scatter the crumble topping from Step 3 evenly over the rhubarb, breaking up any large clumps with your fingers but leaving some texture. Bake for 35 to 40 minutes until the topping is golden brown and the filling is bubbling around the edges. The fruit should be tender when pierced with a fork.
- Remove the crumble from the oven and let it cool for at least 10 minutes before serving—this allows the filling to set slightly and makes it easier to scoop. Serve warm with vanilla ice cream or whipped cream, or enjoy it cold the next day (the flavors actually deepen and the texture improves as it sits).
