Vegan Rhubarb Crumble (Gluten-Free) – Plant Based Jess

This vegan rhubarb crumble is hands down one of the best desserts to enjoy in spring. You’ll love the tangy, creamy rhubarb filling topped with a nutty, crunchy oat crust. It’s simple to make, healthy, and naturally gluten-free—a perfect treat to celebrate the season!

Every spring, I get this rush to cook all things rhubarb! We have two big rhubarb plants in our garden that pop up early, but they don’t stay thick and juicy for long. So, when they’re ready, I try to make the most of our short rhubarb season.

Last year, I had so much fun creating a barley breakfast bowl with a quick strawberry-rhubarb compote for the blog. It was such a hit, we went back to it again this year. But even though rhubarb usually pairs well with other fruits, I wanted to keep it simple this time and let the rhubarb itself shine.

You probably know that rhubarb packs a serious tart punch, so it often pairs with sweeter fruits to balance its sharpness. I’ll never forget as a kid chomping on raw rhubarb stalks straight from the garden—super crunchy, super sour. Who does that, right?!

Okay, I admit, I’d dip each bite in white sugar to help tame the tang, but still, that sourness must have been doing a number on my taste buds back then.

Setting childhood memories aside, this easy rhubarb crumble hits that perfect note of tartness with a touch of vanilla and just enough sweetener to mellow the sharp edges without losing rhubarb’s unique, bright flavor. Plus, it has that cozy, rustic look that makes rhubarb feel extra special. I hope you’ll love this fresh spring treat as much as I do!

Oh, and if you love crumbles, don’t miss trying this vegan pear crumble recipe too!

What You’ll Love About It

What I love about this recipe is how it keeps things wonderfully straightforward while letting rhubarb shine front and center. The filling is bright and creamy thanks to cornstarch, and the topping brings in a lovely crunch with oats, almond flour, and chopped nuts. Plus, it’s naturally vegan and gluten-free, holds up well in the fridge, and you only need a handful of pantry staples to pull it together. It’s just right for those sunny spring or summer days when rhubarb is everywhere. If you’re looking for another simple way to use your rhubarb haul, try these Strawberry Rhubarb Bars.

• Bright and tangy rhubarb flavor that really stands out.
• Crunchy oat-and-nut topping adds fantastic texture contrast.
• Vegan and naturally gluten-free when you use certified gluten-free oats.
• Super easy to scale up or down and great for breakfast or dessert.

If you’re hesitating, let me tell you why this crumble deserves a spot in your kitchen rotation this spring. It celebrates rhubarb with no fuss, comes together super fast with everyday ingredients, and delivers big on taste and texture.

• Rhubarb is the star: The tart, bright flavor stays front and center, balanced just right with a little maple syrup and vanilla that smooths things out without hiding the rhubarb’s unique zing.
• Texture that nails it: You get a creamy fruit layer thickened with cornstarch, paired with a crunchy, nutty oat topping that forms delicious bite-sized clusters thanks to almond flour and coconut oil.
• Simple and flexible ingredients: Only a handful of pantry essentials plus fresh rhubarb — easy to make when rhubarb is in season, and swapping ingredients is a breeze (see my notes section for ideas).
• Vegan and gluten-free by design: Originally vegan, and just use certified gluten-free oats to keep it safe for gluten-free diets.
• Quick and low effort: Just 15 minutes to prep and less than 40 minutes to bake means this is ideal when you want homemade comfort without a long kitchen session.
• Versatile serving options: Enjoy it warm with vegan ice cream or custard, or chill it and serve for breakfast with coconut yogurt or banana “nice cream”—and if you like that vibe, this make-ahead Strawberry Parfait is another bright, fruit-first option.
• Make ahead and store well: You can prep in advance, keep it in the fridge for a few days, or freeze leftovers for later—so handy!
• Feels indulgent but is health-minded: It’s got that satisfying crunchy topping and saucy fruit, but uses whole ingredients and natural maple syrup instead of refined sugar.

All those easy wins combine to make a seasonal dessert that truly shows off rhubarb’s charm, while keeping things approachable, flexible, and absolutely delicious.

Ingredients and Simple Swaps

• 2 tbsp cornstarch – + 2 tbsp water
• ½ cup maple syrup
• 1 tsp vanilla extract
• 5 cups rhubarb – chopped in about ½ inch pieces
• 1 cup rolled oats
• ½ cup almond flour
• ½ cup pecan or walnut – roughly chopped
• pinch of salt
• ¼ cup maple syrup
• 2 tbsp coconut oil – melted

How to Make the Crumble

1. Preheat the oven to 375°F.
2. Remove and discard rhubarb leaves.
3. Peel away any bruised or rough outer layers from the rhubarb stalks as needed.

4. Wash and dry the rhubarb stalks.

5. Chop the rhubarb into ~½-inch pieces.
6. Stir 2 tbsp cornstarch with 2 tbsp cold water until smooth and lump-free.
7. Add maple syrup, vanilla extract, and the cornstarch mixture to the bottom of an 8×10-inch baking dish and stir to combine.

8. Add the chopped rhubarb to the baking dish and stir to coat with the syrup mixture; set aside.

   

9. Melt the coconut oil.
10. In a medium bowl, combine melted coconut oil, rolled oats, almond flour, chopped walnuts, a pinch of salt, and maple syrup; stir until evenly combined and the oats are coated.
11. Spread the crumble topping evenly over the rhubarb mixture and gently press with your hand or a spoon to form clusters.

12. Bake 35–40 minutes, until the topping is golden and the filling is bubbling at the edges, watching near the end to prevent burning.

    

13. Let the crumble cool for 10–15 minutes before serving.

    

Prep, Timing, and Texture Tips

Did you know rhubarb is actually a vegetable? It’s related to sorrel and looks a bit like celery stalks — long, fibrous, and sometimes bright red or greenish with hints of red. What you see is mostly skin color, which doesn’t change the flavor much, though the deeper reds can be a bit sweeter.

Rhubarb grows mainly from March through mid-June, though you might find it year-round in some places, especially if grown indoors. When picking rhubarb — whether at the market or your garden — look for thick, firm stalks that are bright red and free from bruises.

How to prepare rhubarb

Start by removing the leaves, which are toxic because they hold lots of oxalates. Cut them off and toss them—don’t eat those! Next, inspect your stalks and peel off any bruised or rough outer layers. For larger stalks, sometimes peeling away the outer skin (even if it takes off some red color) helps keep your fruit base from getting too stringy or tough. Wash and dry the stalks well before chopping.

For this crumble, I like to cut the rhubarb into small cubes—about half an inch or slightly smaller. This size makes the fruit base nice and creamy after baking, much more pleasant than big chunks.

• Always melt your coconut oil before adding it to the crumble ingredients so it distributes evenly throughout the topping.
• You can use any baking dish you have, but keep in mind that if it’s much smaller or larger than 8 x 10 inches, you might need to adjust baking time. A smaller dish means a thicker crumble, so it could take a little longer to bake.
• Watch the crumble closely towards the end of baking — as with cobblers like this Magic Lemon Cobbler, the topping can go from golden to burnt fast!
• Keep the nuts on the chunkier side to add great texture contrast to every bite.
• If you want to cut back on sugar, try mixing half rhubarb with a sweeter fruit like strawberries, cherries, peaches, or pears. For this combo, use half as much maple syrup (about ¼ cup) to keep the sweetness balanced.

This rhubarb crumble tastes amazing warm or cold. When fresh from the oven, I love serving it with a scoop of vegan ice cream that slowly melts into the warm, tangy fruit. It’s also delicious with coconut whipped cream or a drizzle of vegan custard.

For a breakfast twist, similar to my strawberry chocolate baked oatmeal, you can prepare this ahead of time and enjoy it chilled with a spoonful of banana “nice cream” or coconut yogurt for a refreshing, healthy morning treat. If you enjoy bake-ahead breakfasts, this Blueberry-Lemon Breakfast Cake offers a bright, citrusy option.

Mix-Ins and Substitution Ideas

• Try half rhubarb, half berries: swap up to half the rhubarb with strawberries, raspberries, or cherries. This sweeter fruit mix pairs nicely, just remember to reduce the maple syrup by about half.
• Switch up the nuts: pecans, almonds, or hazelnuts are all tasty alternatives to walnuts. For a nut-free option, replace almond flour with oat flour and add sunflower or pumpkin seeds in the topping.
• Flour swaps: If you don’t have almond flour, use oat flour or a gluten-free all-purpose flour to keep it gluten-free.
• Sweetener swaps: Agave syrup works fine instead of maple syrup, but avoid granulated sugar in the fruit layer, or it might turn soggy.
• Starch swaps: Arrowroot powder is a great substitute for cornstarch to thicken your fruit filling.
• Richer topping: For a more buttery flavor and crisper clusters, swap coconut oil for melted vegan butter.
• Spiced twist: Add a pinch of cinnamon, ground ginger, or some fresh lemon zest to the fruit or crumble topping to brighten things up or add warmth.

Storage, Make-Ahead, and Leftovers

Store any leftovers in a sealed container in the fridge for 4 to 5 days. While the crumble topping is crispiest on day one, it still tastes wonderful after chilling, even if it softens a bit. If you’d prefer a dessert that’s designed to be made ahead and served chilled, try this Vegan Biscoff Cheesecake recipe, which keeps beautifully in the fridge.

Common Rhubarb Questions Answered

• Is rhubarb edible? Yes, but only the stalks. The leaves are toxic and must be removed before cooking.
• Can I use frozen rhubarb? Absolutely! Just thaw it first and drain excess liquid. You might want to add a little extra cornstarch or arrowroot to get that creamy texture.
• Are oats gluten-free? Oats themselves are naturally gluten-free but can get contaminated during processing. Make sure to choose oats that are labeled “certified gluten-free” if you’re avoiding gluten.
• How do I keep the topping from getting soggy? Use old-fashioned rolled oats (not quick oats), press the crumble lightly into clusters before baking, avoid baking in a smaller dish that makes the filling thick, and let the crumble cool for 10-15 minutes after baking so it sets.
• Can I make this ahead or freeze it? You can prep the fruit and topping separately, refrigerate for a few hours, then bake when ready. Leftover baked crumble keeps in the fridge for 4-5 days or freeze it airtight for up to 2 months. Reheat in the oven to restore crunch.
• Can I substitute coconut oil? Yes! Melted vegan butter works well and gives a richer, crispier topping.
• What if I want less sugar? Mix your rhubarb with a sweeter fruit like strawberries or pears and cut the maple syrup in half as I mentioned in the notes above.