A soft and sweet gluten free rhubarb crumb cake that's a wonderful way to make the most of the season. Tart bits of rhubarb, a tender cake, and a buttery, brown sugar streusel topping make it equally acceptable for breakfast or dessert.

This pretty cake is my version of a rhubarb coffee cake, easily made gluten-free and finished with a heaping portion of deliciously buttery crumb topping. It's studded with jammy bits of rhubarb and is unapologetically sweet - think my gluten free rhubarb cake but with a brown sugar crumble to make it perfect for breakfast. This cake is so lovely on the summer brunch table, or enjoyed outside on a sunny morning with a hot cup of coffee.
Make sure to check out my easy rhubarb recipes post for lots more rhubarb recipes!
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What You'll Love
- That topping. Each bite of cake delivers a cinnamon-spiked, brown sugar-sweetened buttery crunch that's never heavy.
- Not your ordinary dessert offering. While gluten free coffee cake or a gluten free blueberry bread certainly has its place, anything made with rhubarb is special because you can only make it during one time of the year. So lean in! Serve this for Mother's Day brunch or bring it to a backyard BBQ.
- Soft and tender texture. No crumbly or dry gluten-free cake here! The cake itself is soft and tender, punctuated by the tart pockets of rhubarb, and the crumb topping lends a bit of crunch without being too much.

Ingredients Needed
Here's what you'll need for this cake. Make sure to scroll down to my recipe card at the bottom of this post for the full ingredient amounts and instructions!
- Butter - Unsalted butter is used in the topping and the cake.
- Gluten-free flour - You can use any 1:1 gluten-free flour mix you prefer. I used my homemade gluten free flour blend, and it worked great.
- Brown sugar - Light or dark brown sugar is fine.
- Ground cinnamon - Or substitute ground ginger.
- Baking powder
- Salt - Fine sea salt or table salt.
- Granulated sugar
- Egg - A large or medium egg is best.
- Vanilla - Use pure vanilla extract or vanilla bean paste.
- Milk - I prefer whole milk for richness, and 2% milk is also fine.
- Rhubarb - Choose firm rhubarb with no brown spots. Frozen rhubarb can be used if needed.
Variations to Consider
- Add strawberries - Make this into a strawberry rhubarb crumb cake - like in my gluten free strawberry rhubarb cake, these two were meant to be together. Swap ½ cup chopped rhubarb for ½ cup chopped strawberries.
- Orange zest - Rhubarb also loves orange. Zest 1 orange into the sugar, rub it in to release the oils, then proceed with the recipe. Or try lemon zest.
- Walnuts - For a little bit of crunch, stir in ½ cup chopped (toasted or untoasted) walnuts to the batter.

Step-by-Step Instructions
Here's an overview in photos of how to make a gluten free rhubarb crumb cake:

1. Make topping: Mix the topping ingredients, then chill in the fridge.

2. Combine dry ingredients: In a small bowl, whisk together the flour, baking powder, and salt.

3. Cream butter: In a separate bowl, cream the butter and sugar, then add the egg.

4. Combine: Add the flour mix and fold in the rhubarb. Place batter in a lined 8x8-inch pan.

5. Add topping: Sprinkle the topping over the batter.

6. Bake: Place in a 350F oven and bake for about 40 minutes.

Tips & Recipe Notes
- Keep the topping in the fridge. After assembling the crumb topping, keep it in the fridge so it firms up a bit while you make the cake. This helps the flour to hydrate and the butter to chill, which will make for big, buttery bits of crumble later. You may need to break up the topping with your hands before sprinkling it over the top of the cake.
- Can I use frozen rhubarb? Yes - frozen rhubarb works great in this cake. No need to defrost it first, just stir it into the batter.
- Rest the batter. As always with gluten-free bakes, it's a good idea to rest the batter for at least 15 minutes before baking. This helps achieve that soft and fluffy crumb!
- To serve: With whipped cream, a drizzle of salted caramel sauce, a scoop of vanilla ice cream, or it's just perfect as-is!
Proper Storage
- Counter - Cover the pan of cake tightly with foil, or transfer it to an airtight container, and store on the counter for up to 2 days.
- Fridge - The cake will last a bit longer, covered or in an airtight container, in the fridge, for up to 5 days.
- Freezer - Wrap the cake in foil, then freeze for up to 2 months. Thaw in the fridge before serving.
More Gluten Free Rhubarb Recipes
Happy baking! If you make this gluten free rhubarb crumb cake recipe, I'd love to know. Please leave a comment below, reach out with any questions, and tag me on Instagram @Cucina Nicolina ❤️
Recipe

Gluten Free Rhubarb Crumb Cake
Ingredients
Topping
- 6 tablespoons unsalted butter melted
- 1 ¼ cup gluten free flour (140 grams)
- ½ cup brown sugar
- 1 teaspoon ground cinnamon
Cake
- 1 ¾ cup gluten free flour (210 grams)
- 1 ½ teaspoon baking powder
- ½ teaspoon fine sea salt
- 4 tablespoons unsalted butter , room temperature
- ¾ cup granulated sugar
- 1 large egg
- 2 teaspoons pure vanilla extract
- ⅔ cup whole milk
- 1 ½ cups rhubarb , cut into ½ inch pieces
Instructions
- Preheat oven to 350℉. Butter an 8-inch square baking pan and line the bottom with parchment paper.
- Make the topping: In a medium bowl, stir together 6 tablespoons unsalted butter, 1 ¼ cup gluten free flour, ½ cup brown sugar, and 1 teaspoon ground cinnamon until combined. Place in the fridge so it can firm up a bit.
- Make the cake. In a medium bowl, whisk together the 1 ¾ cup gluten free flour, 1 ½ teaspoon baking powder, and ½ teaspoon fine sea salt. In a large bowl with an electrix mixer on medium speed, cream the 4 tablespoons unsalted butter and ¾ cup granulated sugar until fluffy, then beat in the 1 large egg and 2 teaspoons pure vanilla extract.
- Add the flour mixture to the creamed mixture in 2 additions, alternating with the ⅔ cup whole milk. Beat well to combine. Fold in the 1 ½ cups rhubarb.
- Spread the batter in an even layer into the prepared pan. Take the topping out of the fridge; it will be solidified. Using your hands, break it up and crumble it evenly over the top of the batter.
- Place in the oven and bake for about 40 minutes, until a tester inserted in the center comes out mostly clean. Let cool in the pan set on a wire rack to room temperature.
Notes
- Keep the topping in the fridge. After assembling the crumb topping, keep it in the fridge so it firms up a bit while you make the cake. This helps the flour to hydrate and the butter to chill, which will make for big, buttery bits of crumble later. You may need to break up the topping with your hands before sprinkling it over the top of the cake.
- Can I use frozen rhubarb? Yes - frozen rhubarb works great in this cake. No need to defrost it first, just stir it into the batter.
- Rest the batter. As always with gluten-free bakes, it's a good idea to rest the batter for at least 15 minutes before baking. This helps achieve that soft and fluffy crumb!
- To serve: With whipped cream, a drizzle of salted caramel sauce, a scoop of vanilla ice cream, or it's just perfect as-is!









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