Tangy-sweet rhubarb apple crisp recipe topped with a crunchy oat and brown sugar topping. It's a classic recipe perfect for celebrating the short rhubarb season. Serve it with vanilla ice cream or vanilla sauce.
The rhubarb apple crisp is a tasty dessert that combines the tartness of rhubarb with the sweetness of apples, topped with a crispy crumble topping.
This is an updated recipe that was first posted in 2018.
I do have a soft spot for rhubarb desserts, either a crisp like today’s rhubarb apple crisp, a crumble like my favorite Apple Rhubarb Crumble, or a pudding with custard like this Baked Rhubarb Custard.
Over the years, I have made so many fruit crumbles or fruit crisps that I have lost track of them all.
What is the difference between a crisp and a crumble?
They are very similar, crumble being a name used mainly in the UK.
However, there is a slight difference between the two: a crisp is usually made with oatmeal/ rolled oats, while a crumble is a streusel-like topping made with flour (all-purpose or whole-wheat), sugar (white or brown), and butter.
Another difference is that, as the name already says, a crisp would be crispier due to the rolled oats that crisp up during the baking process.
Another similar dessert is a cobbler. The cobblers are fresh fruit topped with a biscuit topping and baked in a casserole dish. Other versions of cobblers are made with cake batter (like this Easy Red Currant Cobbler with Almonds) or with cookie dough.
- Rhubarb is a vegetable often used as a fruit in cooking and baking due to its tart flavor. When cooked, it becomes soft and releases a tangy, slightly sour taste that adds a delightful contrast to the sweetness of the apples in the crisp.
- Apples: Choose apples that hold their shape during baking, like Granny Smith, Honeycrisp, or Braeburn apples. The apples contribute natural sweetness and a pleasant texture to the dessert.
- Granulated sugar for mixing with the rhubarb pieces before baking them and some for the crisp.
- Cornstarch: It helps to bind the fruit juices and creates a cohesive texture in the filling as it bakes.
- All-purpose flour: Adding flour to the crisp topping contributes to its texture, structure, and flavor, resulting in a delicious and satisfying contrast to the fruit filling.
- Brown sugar adds a rich, caramel-like taste to the crumble topping, creating a delicious contrast to the tartness of the fruit. You will also need some white sugar for the crisp.
- Butter: Butter adds richness and helps create a crisp and buttery texture when combined with flour, oats, and sugar.
- Oats: Old-fashioned oats are rolled oats that add texture and a nutty flavor to the crumble topping.
- Optional spices: Add one teaspoon of ground cinnamon and a pinch of nutmeg to the crisp mixture. You could also use allspice, cardamom, or a bit of ground ginger.
How to make apple rhubarb crisp?
- Place the chopped rhubarb in a large bowl, mix it with granulated sugar, and let it release its juices for about 15-20 minutes.
- In the meantime, preheat the oven, chop the apples, and make the topping.
- Drain the rhubarb well to remove all excess liquid.
- Toss apples, rhubarb, and vanilla extract. Mix and transfer the mixture to the baking dish.
- Mix the oats, flour, both types of sugar, and salt in another bowl.
- Add the chopped cold butter. Stir to coat the butter cubes in the flour and oat mixture, then cut in the butter using two knives or rub the butter into the mixture using your fingertips until you get coarse crumbs.
- Alternatively, make the crisp in a food processor.
- Top the fruit mixture with the butter, oats, and flour mixture.
- Bake the apple rhubarb crisp for 15 minutes.
- Lower the heat to 320°F/ 160°C and bake the rhubarb apple crisp with oats for another 15 minutes or until golden brown.
- Let cool shortly before serving.
Rhubarb leaves are poisonous; always discard them.
- Drain the sugared rhubarb slices well before you add them to the baking dish. Too much juice will make the crisp soggy.
- Adding some cornstarch will also help against the sogginess; the rhubarb slices should be coated in a thin layer of cornstarch.
- Balance the sweetness: Rhubarb can be pretty tart, so it's essential to balance the sweetness of the crisp.
- Adjust the amount of sugar according to your taste and the tartness of the rhubarb. You can add more sugar if you prefer a sweeter crisp or if your stalks are particularly tart.
- Customize the topping: Add chopped nuts (such as almonds, pecans, or walnuts) or a handful of shredded coconut. They will provide extra texture and flavor to the rhubarb apple crisp.
- Baking dish sizes: Use a baking dish that provides enough space to accommodate the fruit filling and the crumble topping while allowing for even baking, in this case, about 8x12 in/ 20x32 cm.
- However, you can use a slightly smaller baking dish if you prefer a thicker crisp.
- Remember that the baking time may need to be adjusted accordingly if you use a different-sized dish.
Yes. Frozen fruit usually releases more water than fresh fruit, but this will not be an issue, as you will drain it.
Chop the rhubarb into small pieces, place them in a freezer bag, flatten the bag a bit, and freeze it.
Martha Stewart (the link opens in a new tab) would advise you to lay the pieces on baking trays lined with baking paper, freeze them for several hours, and transfer them to freezer bags once solid; this way, the slices will not stick together when frozen. However, I rarely bother.
For more details on this subject, check How to Freeze Rhubarb.
Refrigerate the baking dish (covered with plastic wrap) for 3-4 days. Or transfer the leftovers to an airtight container.
Serve the leftover rhubarb apple crisp at room temperature or reheat them.
Reheat in the preheated oven (350°F/175°C) for about 15 minutes or until heated through. Keep an eye on the topping; cover the baking dish with aluminum foil if it gets too dark.
What to serve with it?
- You can have the rhubarb apple crisp just as it is, either warm or at room temperature.
- Or you can serve it warm with a scoop of vanilla ice cream that will melt slowly on top and bring it to a whole new level.
- Top with whipped cream, runny cream, vanilla sauce, or vanilla custard.
- Or a personal favorite of mine: mix some crème fraiche with a bit of brown sugar, and let the mixture stand for a short while until the brown sugar dissolves in the crème fraiche. A divine combination!
More rhubarb desserts
Rhubarb Apple Crisp with Oatmeal
- Baking dish about 8x12 in/ 20x32 cm, Note 1
Rhubarb apple mixture:
- 2 lbs rhubarb 1 kg
- ⅓ cup white granulated sugar 75 g/ 2.5 oz
- 2 lb apples 1 kg, Note 2
- 1 teaspoon vanilla extract
- 2 tablespoons cornstarch
- 1 cup old-fashioned oats 100 g/ 3.5 oz, Note 3
- ½ cup all-purpose flour 60 g/ 2 oz
- ½ cup brown sugar 90 g/ 3 oz, Note 4
- ½ cup white granulated sugar 100 g/ 3.5 oz
- a pinch of salt
- ½ cup unsalted butter cold, 120 g/ 4 oz
- Rhubarb: Clean and chop it into 2 cm/ ¾ inch pieces. Place the pieces in a bowl and sprinkle them with sugar. Mix well and let the rhubarb release its juices for about 15-20 minutes. 2 lbs/ 1 kg rhubarb + ⅓ cup/ 75 g granulated sugar
- In the meantime, preheat the oven to 350°F/ 175°C, chop the apples, and make the crisp.
- Apples: Chop them into small cubes.1 lb/ 1 kg apples
- Drain the rhubarb well, add apples and vanilla extract. Mix and transfer the mixture to the baking dish.1 teaspoon vanilla extract
- Combine dry ingredients: Place the oats, flour, both types of sugar, and salt in a bowl. Mix well (Note 5).1 cup/ 100 g oats + ½ cup/ 60 g flour + ½/ 90 g brown sugar + ½/ 100 g white sugar + pinch of salt
- Add butter: Cube the cold butter and add it to the mixture. Stir to coat the butter cubes in the flour and oat mixture, then cut in the butter using two knives or rub the butter into the mixture using your fingertips (alternatively, use a food processor).½ cup/ 120 g butter
- Top the filling with the crisp mixture.
- Bake for 15 minutes, then lower the heat to 320°F/ 160°C and continue baking the rhubarb apple crisp for 15 more minutes or until golden brown.
- Let cool shortly before serving.
- Serve warm or at room temperature with one ice cream, vanilla sauce, heavy cream, or crème fraiche mixed with brown sugar.
- Baking dish sizes: Use a baking dish that provides enough space to accommodate the fruit filling and the crumble topping while allowing for even baking, in this case, about 8x12 in/ 20x32 cm. However, you can use a slightly smaller baking dish if you prefer a thicker crisp. Just keep in mind that the baking time may need to be adjusted accordingly if you use a different-sized dish.
- Apples: Choose apples that hold their shape during baking, like Granny Smith, Honeycrisp, or Braeburn apples.
- Sugar: You can use only white sugar instead of a mixture of brown and white sugar. Just replace the brown sugar with the same amount of white sugar.
- Optional: Add one teaspoon of ground cinnamon and a pinch of nutmeg to the crisp mixture. You could also use allspice, cardamom, or a bit of ground ginger. Add chopped nuts (almonds, pecans, or walnuts) or a handful of shredded coconut.