Rhubarb Crumble with Apple (2024)

The only thing I make when rhubarb season arrives – rhubarb crumble! I like to add apple into mine so the filling isn’t just baby-food-mush. Adore the tangy filling – there is nothing else like it. Serving with ice cream is a MUST!

There’s nothing like rhubarb!

This is one of those rare recipes where I can’t offer flexibility – because there is no substitute for rhubarb! There’s nothing like it – the unique celery-like texture, bright red colour and signature tang. Even its cooking qualities are unusual. It goes from apple-like crispy to very soft, with seemingly no in-between “tender crisp” like you get with most fruit.

Which, I just realised, might sound unappetising. 😂 But actually, the softness when cooked is is what makes it such a great filling for a crumble. Though also, it is the reason why I like to combine it with apple, to give it some much needed texture.

For those of you new to rhubarb…..

• What it is – A vegetable, but mostly used for desserts! Looks like celery except with red stalks.

• Flavour – Tart, like lemon but less sour. You wouldn’t eat a pie filled with lemon flesh, way too sour! Whereas you can, with rhubarb.

• Why people love it – The striking colour and unique tangy flavour, quick to cook (hard to soft in 5 minutes on the stove), easy to prep (no peeling, just cut the stalk).

• What it’s used for – Mostly desserts. Crumble is a common use – I’m so unoriginal, I know. Either just rhubarb, or combined with other fruit – apple and strawberry are favourites. Why? Partially for texture (rather than having a dish full of just very soft rhubarb which some people – ahem, me – likens to baby food) and also perhaps price (rhubarb is $5-$6 a bunch, you need 2 to make a rhubarb-only crumble).

  It’s also used stewed, like a compote and jams, for decorating (think: red stalks baked on top of cakes, muffins, pastries), tarts.

• How to use it – Usually cooked, though can be eaten raw, I had it in salads. When cooked it’s soft, the tangy flavour is tempered and juicier.

• How to cook it – Baked, stewed. When cooked it’s so soft it does not hold its shape when picked up. Chopped pieces breaks down into a jam-like consistency within 5 minutes on the stove.

• When it’s in season – Opposite times in opposite parts of the world!
  – Aust/NZ: late winter to spring (June – Sept)
  – US/UK/northern hemisphere: spring to summer (April – June)
  – Forced rhubarb: UK early variety, Jan – Mar. Grown in the dark rather than outdoors. More tender, pink rather than red and juicier. Haven’t tried this crumble recipe with it as it doesn’t exist in Australia. Suspect adjustments required including less sugar and juice thickener. Suggest using Nigella’sforced rhubarb crumble recipeinstead.

• Grows like a weed. Un-killable, I’m told. Try planting some!

Ingredients in Apple & Rhubarb Crumble

See the section above for rhubarb chatter. This section will cover everything else!

• Rhubarb – Chatter per above. You will need one big bunch, about 10 – 12 stalks. Sometimes the bunches are small and dismal so rummage around for the biggest and best. Look for celery-like firm stems, not floppy dehydrated ones (juice-less). You need 4 1/2 – 5 cups once the stems are cut. If you’re a little short, that’s ok. The crumble will still work fine! You could also go a little more too.

• Granny Smith (green apples) – As noted above, I like combined rhubarb with another fruit to give some texture to the filling. Otherwise it’s just a big dish of very soft rhubarb which has a texture like apple puree when you eat it.

  Granny Smith is my choice for its tartness (matches the rhubarb) and ability to hold its shape when cooked.

• Sugar – To balance the tang of the rhubarb and green apple, and to create a syrup with the juices.

• Orange zest – Optional! Adds a little citrus zing.

No syrup thickener – Early versions of rhubarb crumble used cornflour/cornstarch or flour to thicken the juices I expected to come out of the rhubarb as it baked. But actually, rhubarb isn’t as juicy as apple, strawberry, peach and other fruits I use in crumbles and cobbler recipes. So it made the filling pasty rather than creating a syrup sauce. Turns out, you don’t need it. The majority of the juiciness of rhubarb stays inside the barely-holding-together cooked rhubarb pieces that bursts out in your mouth when you bite into it!

Crumble topping

This crumble topping has less butter in it than my classic apple crumble topping so it’s crisper. Reason: the more buttery crumble steals the juice from the rhubarb which a) makes the topping “doughy” on the underside and b) rhubarb filling lacks juice. It took multiple iterations (“the crumble is pasty!!” 😝) before we figured this out!!

• Roll oats – Just regular oats. Not steel cut, not quick cook.

• Brown sugar – For better caramely flavour and colour for the topping. But can be substituted with white sugar.

• Butter – For buttery goodness and the wet ingredient that brings the crumble mixture together.

• Baking powder – To give the topping a bit of lift, otherwise it is a little too rock hard!

• Flour – Plain/white flour. Almond meal works well as a gluten free substitute.

• Cinnamon – Mandatory in virtually every crumble I make!

• Salt – Just a pinch, to bring out the flavours.

How to make Apple & Rhubarb Crumble

Nice and easy. Rhubarb is so easy to prepare!

1. Rhubarb – Wash the rhubarb stems. Trim off the dirty end. Then cut into 4cm / 1.5″ even lengths. Discard the leaves – they should not be eaten.

2. Toss the rhubarb with apple pieces, sugar and orange zest in a large bowl. Then spread in a 30 x 20cm baking dish (12 x 8″).

   Baking pan size – If you don’t have a pan of this size, go smaller rather than larger. If the pan is too big, then the filling layer gets too thin and will be a little less juicy than ideal (the crumble topping absorbs some of juices).

3. Crumble topping – Put all the crumble topping ingredients in a bowl and mix until you no longer see flour. As noted above in the ingredients section, this mixture has less butter than my classic crumble topping. So you’ll need to mix a little longer. Smear up the sides of the bowl and use a cutting motion as needed to get it all mixed up.

4. Chunky bits! Grab handfuls of the crumble mixture and enclose in your first to press together. Then use your fingers to break into clumps to cover the surface.

   Why I do this strange step? Couple of reasons! Firstly, as mentioned earlier, rhubarb is less juicy than typical fruits used in crumbles (like apple) so I don’t want sandy crumble topping falling into the rhubarb and stealing the precious juices. It makes the filling pasty, as I found out firsthand.

   Secondly, the topping for rhubarb crumble is sandier (for reasons outlined in the ingredients section) but I still want the crumbly chunks for crunch rather than a layer of dry sand. Solution? Scrunch in hands, then crumble. Easy! 🙂

5. Cover surface with the crumble mixture.

6. Bake for 35 minutes until the crumble topping is golden, the rhubarb is tender and you see red juices bubbling up the sides. Poke the rhubarb with a butter knife to check! Sometimes, firmer and thicker pieces of rhubarb can take an extra 5 minutes but 35 minutes is consistently the perfect bake time for me.

   Rest for 5 minutes before serving. This let’s it cool down slightly as well as giving the juices a chance to thicken slightly.

IMPORTANT serving point!

With every crumble recipe I’ve shared, I very strongly recommend serving with ice cream – or custard.

With rhubarb crumble, it’s not a strong recommendation. It’s a must! The tartness of the filling demands something creamy to balance it out. And also, the filling is not as juicy and syrupy as other crumble fillings because, as I’ve repeated a bizarre number of times throughout this post, rhubarb just isn’t as juicy as other crumble fruits like apple, strawberry, peaches etc.

So I’m not urging you to serve with ice cream or custard. I’m making it mandatory. Please promise me you won’t skip it! 🙂 – Nagi x

Watch how to make it

Other members of the crumble and cobbler family

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