This sourdough apple crisp is the kind of dessert you make when you want maximum comfort for minimum faff. Soft, cinnamon-spiced apples sit in a glossy sauce under a buttery, oat-flecked topping that goes properly crisp in the oven. It takes about an hour, and most of that is the oven doing the work.

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I've made a fair few versions of this over the years, some with a topping that stayed soft, some with a filling that never quite set. This one uses sourdough discard in both the apples and the crumble, which sorts out both problems at once. Whether you call it a crisp or a crumble is entirely up to you.

Recipe Highlights
TASTE: Glossy, spiced apples under a buttery, craggy oat crumble
DISCARD'S JOB: Thickens the filling, binds the topping, no eggs or baking powder needed
SEB'S RATING: Vanilla ice cream is the only topping for this sourdough apple crisp.
Crisp or Crumble? (And Why It Doesn't Really Matter)
If you grew up calling this a crisp, you're likely American. If you grew up calling it a crumble, you're probably from the other side of the ocean. Either way, you're talking about the same thing: fruit baked under a buttery, oat-and-flour topping until it's golden and crunchy on top.
The distinction gets muddier the more you look at it. Some American recipes leave the oats out entirely, which technically makes it a crumble by British standards. Some British crumbles add oats for texture, which nudges them towards crisp territory.
This recipe sits happily in the overlap: sourdough apple crumble if that's what you call it at home, sourdough apple crisp if it isn't. The topping is the same either way, buttery, clumpy, and full of sourdough discard.

Ingredient Notes and Substitutes
- Apples: Granny Smith hold their shape and give you distinct, tender-not-mushy chunks. Bramley (or another cooking apple) breaks down more, giving a softer, saucier filling if that's what you prefer. We used Granny Smiths here, as we do in our Sourdough Apple Scones and Sourdough Apple Pie too!
- Sourdough discard, twice over: It appears in the filling, whisked with hot apple juice to loosen it before it thickens the whole pan into a glossy sauce. It appears again in the topping, where it binds the crumbs into clumps without needing egg or baking powder to do the job.
- Oats: Rolled oats give the topping its craggy texture and most of its crunch. Quick oats will work in a pinch but bake down softer, with less bite.

Find the full ingredient quantities, step-by-step instructions and nutritional information in the recipe card below.
A Note on Pan Size
This is genuinely sized for a 20cm (8 inch) square dish. That matters here: too shallow a filling and the topping burns before the apples soften properly.

If you want to feed a crowd, double everything and bake in a 9x13 inch (23x33cm) dish instead of trying to stretch this quantity across it. For something similarly low-effort, my Slow Cooker Sourdough Apple Cobbler and Stovetop Sourdough Apple Upside Down Cake are worth a look, and they don't even need the oven at all.
Storage
This keeps covered at room temperature for up to 2 days, or in the fridge for up to 5. Reheat individual portions in the oven or a hot air fryer before serving to bring the topping back to something crisper than a microwave will give you.
Don't freeze the baked dish. The apples turn watery on thawing and the topping never really recovers. The topping alone, unbaked, freezes well for up to a month, so it's worth making a double batch of that if you bake this often.
Recipe FAQs
Yes. Active starter and discard behave the same way here since there's no rise involved, just thickening and binding. Use whichever you have to hand.
For the smoothest filling, yes. The skins soften as they cook but stay noticeably chewier than the flesh, which most people don't want in a crisp.
Swap the oats for an equal weight of extra plain flour, and add an extra 15g of cold butter to keep the topping from turning dry. You'll lose some of the craggy texture, but it will still crisp up.
In practice, very little. Both are fruit baked under a buttery topping. American recipes calling it a crisp usually include oats, while British crumbles traditionally don't, though plenty of modern crumbles do include them too. This recipe sits in the overlap and works for either name.
Usually one of two things: the filling was too wet going in, or the topping wasn't chilled properly before baking. Chilling firms up the butter so it holds its shape in the oven instead of melting flat before the crumbs have a chance to crisp.
More Apple Sourdough Recipes
Craving autumnal apple bakes this season? Try Sourdough Apple Scones or Sourdough Apple Muffins next! We have plenty of fall sourdough recipes featuring this humble fruit:
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Sourdough Apple Crisp (Sourdough Crumble)
Equipment
- 20cm (8 inch) square baking dish
- Medium saucepan
Ingredients
For the apple filling:
- 800 g (1¾ lb) Granny Smith or Bramley apples * ( 5-6 medium), peeled, cored and sliced about 5mm thick
- 75 g (⅓ cup, packed) soft light brown sugar
- 2 teaspoon lemon juice
- ¾ teaspoon ground cinnamon
- pinch of salt
- 45 g (3 tablespoon) sourdough discard 100% hydration
For the sourdough crisp (crumble) topping:
- 130 g (1 cup) all-purpose flour (plain flour)
- 85 g (1 cup) rolled oats
- 85 g (½ cup) soft light brown sugar
- ½ teaspoon ground cinnamon
- pinch of salt
- 95 g (6½ tbsp (¾ stick)) unsalted butter, cubed
- 70 g (⅓ cup) sourdough discard 100% hydration
Instructions
- Preheat your oven to 190°C (375°F). Butter your 20cm (8-inch) square baking dish.
- Put the sliced apples, sugar, lemon juice, cinnamon and salt into a medium saucepan. Cook over medium heat for 7-8 minutes, stirring occasionally, until the apples have started to soften and released their juices.
- Whisk the sourdough discard with 1-2 tablespoons of the hot apple juice from the pan to loosen it, then stir it back into the apples. Cook for a further 2 minutes, stirring, until the juices thicken and coat the apples in a glossy sauce. Take off the heat and tip into your prepared dish.
- For the topping, mix the flour, oats, sugar, cinnamon and salt together in a bowl. Rub in the cold butter with your fingertips until you've got a mix of fine crumbs and larger, pea-sized pieces.
- Add the sourdough discard in two or three additions, tossing with a fork first, then squeezing gently with your hands to bring the mixture into a mix of large and small clumps. Don't overwork it into a dough, you want clumps, not paste.
- Cover and chill for 15-20 minutes.
- Scatter the chilled clumps over the apple filling, leaving some gaps rather than pressing it into an even layer.
- Bake for 35-40 minutes, until deep golden and crisp on top and the filling is bubbling at the edges.
- Rest for 10 minutes before serving. Best warm, with custard, cream or vanilla ice cream.
Notes
Nutrition












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