Apple Rhubarb Crisp (Easy, Crowd-Pleasing, and Perfect for a 9x13 Pan)
This easy apple rhubarb crisp delivers the perfect balance of sweet and tart in every bite, topped with a buttery, crumbly oat topping that bakes up golden and irresistible. Great for fresh or frozen rhubarb, and simple enough to make any night of the week.
The Tart-Sweet Baked Dessert You Will Make on Repeat
There is something deeply comforting about a fruit crisp. No fussy pastry dough, no blind baking, no precise lamination. Just luscious, bubbling fruit underneath a crumble topping that shatters when you press a spoon through it. This apple rhubarb crisp hits every note: the tartness of rhubarb, the natural sweetness of apple, a generous pour of brown sugar, and a buttery oat topping with just enough crunch to make every bite interesting.
Whether you have fresh stalks from the garden or a bag of rhubarb crisp using frozen rhubarb pulled straight from the freezer, this recipe handles both beautifully. It scales up to a full 9x13 pan, which makes it ideal for potlucks, family dinners, or honestly just keeping in the fridge all week because you deserve it.
Why Apple and Rhubarb Are a Perfect Pair
Rhubarb is famously tart, and on its own it needs a substantial amount of sugar to be palatable in desserts. Apples, especially a firm variety like Granny Smith or Honeycrisp, bring their own natural sweetness and a soft, jammy texture as they bake. Together they balance each other out, so you end up using less added sugar overall while still getting that bright, punchy flavor that makes a rhubarb crisp easy enough to justify making again and again.
The filling does not need much. Just sugar, a little cornstarch to thicken the juices as the fruit bakes down, vanilla, and cinnamon. Straightforward ingredients, serious flavor.
Chef's Tip: Granny Smith apples hold their shape during baking better than sweeter varieties. If you want more texture in every bite, they are the right call. If you prefer a softer, more saucy filling, go with Golden Delicious or Fuji.
The Secret to a Truly Crunchy Crumble Topping
The topping is where a rhubarb crunch crumble topping recipe either wins or falls flat. The two biggest mistakes people make are using instant oats (too mushy) and warm butter (no texture). This recipe calls for old-fashioned rolled oats and cold butter, worked in by hand until the mixture looks like rough, clumpy sand. Those small cold butter pockets are what create the crackling, golden crust you are after.
This is also a flexible 5-ingredient rhubarb crisp concept at its core: fruit, sugar, oats, flour, and butter. Everything else is just seasoning.
Having the right tools makes this even easier, and the right baking dish is more important than it sounds when making a rhubarb crisp for a 9x13 pan.
Fresh vs. Frozen Rhubarb: What You Need to Know
If you are working with rhubarb crisp with frozen rhubarb, there is one non-negotiable step: drain it thoroughly. Frozen rhubarb releases a significant amount of water as it thaws, and if that liquid goes into your baking dish, your filling will be soupy and your topping will steam rather than crisp.
Simply thaw the rhubarb in a colander over a bowl, press it gently, and discard the drained liquid. From there, treat it exactly like fresh. You will not notice any difference in the finished crisp.
For a variation, try swapping half the apples for fresh strawberries to make a maple-sweetened strawberry rhubarb crisp style filling. Just replace the granulated sugar with an equal amount of pure maple syrup and reduce it slightly, as maple syrup is more liquid than sugar.
Ready to bake? Here is everything you need, right below:
Apple Rhubarb Crisp (Easy, Crowd-Pleasing, and Perfect for a 9x13 Pan)
This easy apple rhubarb crisp delivers the perfect balance of sweet and tart in every bite, topped with a buttery, crumbly oat topping that bakes up golden and irresistible. Great for fresh or frozen rhubarb, and simple enough to make any night of the week.
Ingredients
- 4 cups rhubarb stalks, fresh or frozen, sliced into 0.5-inch pieces
- 3 apples, peeled, cored, and diced; Granny Smith or Honeycrisp recommended
- 3/4 cup granulated sugar, for the fruit filling
- 2 tbsp cornstarch
- 1 tsp vanilla extract, pure, not imitation
- 1 tsp ground cinnamon, divided between filling and topping
- 1 1/2 cups old-fashioned rolled oats, do not use instant oats
- 3/4 cup all-purpose flour
- 3/4 cup packed brown sugar, light or dark both work
- 1/2 cup unsalted butter, cold, cut into small cubes
- 1/4 tsp salt
Instruction
Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish with butter or nonstick spray.
If using frozen rhubarb, thaw it completely and drain off any excess liquid before measuring. This prevents a watery filling.
In a large bowl, combine the sliced rhubarb, diced apples, granulated sugar, cornstarch, vanilla extract, and 0.5 tsp of the cinnamon. Stir until the fruit is evenly coated. Pour into the prepared 9x13 baking dish and spread into an even layer.
In a separate bowl, combine the rolled oats, flour, brown sugar, remaining 0.5 tsp cinnamon, and salt. Stir to mix.
Add the cold cubed butter to the oat mixture. Using your fingertips or a pastry cutter, work the butter into the dry ingredients until the mixture resembles coarse, clumpy crumbs with some pea-sized butter pieces remaining.
Sprinkle the crumble topping evenly over the fruit filling, covering it completely all the way to the edges of the pan.
Bake for 40 to 45 minutes, until the topping is deep golden brown and the fruit filling is bubbling around the edges.
Remove from the oven and let the crisp rest for at least 10 minutes before serving. This allows the filling to thicken slightly.
Equipment
- 9x13-inch baking dish
- Large mixing bowl
- Medium mixing bowl
- Pastry cutter or fork
- Chef's knife and cutting board
- Measuring cups and spoons
Notes
Serving and Storing Your Apple Rhubarb Crisp
Serve warm with a generous scoop of vanilla ice cream or a dollop of lightly sweetened whipped cream. The contrast between the warm, bubbling filling and the cold cream is one of those simple pleasures that never gets old.
Leftovers reheat well both in the microwave and the oven. If you want to recapture that topping crunch, go with the oven. Cover the dish loosely with foil to warm the filling, then uncover for the last 5 minutes to re-crisp the top.
Make-ahead tip: Assemble the crisp fully in the pan, cover tightly, and refrigerate for up to 24 hours before baking. It is an effortless way to get a showstopping dessert on the table without any day-of stress.
