Rhubarb Crumble Cake

Tart rhubarb, crunchy crumble, and a rich, moist sponge – this cake has a lot to offer!

Rhubarb Crumble Cake


The local rhubarb season is still going strong, and what a season it’s been! I still have a bag full of rhubarb waiting to be used, courtesy of my dad’s garden. I need to be quick about it too – courgette season is almost upon us, which will be even more productive by the looks of things. Produce anxiety, is that a thing?

This cake is traditional loaf cake at heart, designed to be eaten over the course of a few days – if it lasts that long! The addition of rhubarb crumble sets it apart, making it equally at home served warm with custard. Personally I’m a big fan of opening the cake tin and peeling back the paper to find you still have a slice or two of cake left to enjoy with a cup of tea. It happens occasionally.

No dainty slices here – you want a piece you can get your teeth into

The cake itself is rather dense, with a nice crumb, which lends itself well to supporting the double topping of stewed fruit and crumble. The rhubarb is tart, even with the addition of sugar, and if you are lucky you will end up with dark edges where the rhubarb has caught against the side of the pan and turned to smoky caramel. The crumble topping begins as crunchy and relaxes into something chewier as the cake ages.

And boy does this cake age well! I like to leave it for at least a day before cutting, and it can happily sit in a cool, dark place for up to five days as long as it’s well wrapped.

I’ve used buttermilk in this recipe, but you can use ordinary milk without any ill effects. This cake always takes longer than I expect to bake. Once the cake has been in the oven for 45 minutes, insert a skewer or sharp knife. If it comes away clean, the cakes is ready. If it has batter clinging to it, give the cake another 10-15 minutes before testing again. Thanks to the density of the topping, there is very little danger of the cake over baking.

rhubarb crumble cake 1
If the edges catch, be prepared for caramelised rhubarb




100g / 3 ½ oz unsalted butter, softened

170g / 6 oz golden caster sugar

1 tsp baking powder

170g / 6 oz self raising flour

2 large eggs

4 tbsp buttermilk

Rhubarb topping:

2 – 3 medium stalks rhubarb

30g / 1oz white sugar, or more to taste.


60g / 2 oz plain flour

30g / 1 oz butter

30g / 1 oz golden caster sugar


Pre-heat the oven to 180°C / 350°F. Grease and line your loaf tin.

Prepare the rhubarb and the crumble before you begin on your cake batter so that everything is to hand when you come to assemble your cake.

Wash and trim the rhubarb. Cut into 1 inch / 2cm long slices and place in a saucepan over a medium heat. Add the sugar. You are likely to need some liquid to persuade the rhubarb to stew, however the amount you will need annoyingly depends upon the rhubarb itself. Start by adding a tablespoon, and add spoon by spoon if the pan seems dry. I tend to use water, however orange juice or even pineapple juice work well and bring a little extra sweetness while matching the tartness of the rhubarb.

Stir until the majority of the pieces have broken down into gloopy, stringy mess, then remove from the heat and allow to cool while you prepare the other ingredients.

To make the crumble, measure the butter and flour into a large bowl. If the butter is hard, use a butter knife to ‘cut’ it into the flour, until there are no large pieces left. Rub the mix between your fingertips until the butter is worked in and the mix resembles breadcrumbs. Stir in the sugar. Place on one side.

In a fresh mixing bowl, cream the sugar and butter together. Sift in the flour and baking powder and stir to combine. Crack in both eggs, followed by the buttermilk, and beat until smooth.

Pour the batter into your prepared loaf tin and use a spatula or the back of your wooden spoon to smooth the surface.

Spread roughly 7oz / 200g of sweetened stewed rhubarb across the top of the sponge mix using a rubber spatula to smooth into an even layer. Sprinkle the crumble mix over the top. You want the crumble to be rather hearty to stand up to the other layers, so don’t shy away from using all of it.

Bake in a pre-heated oven for 45 minutes. After this time has elapsed, test the cake using a skewer or the blade of a sharp knife. If this comes away clean, the cake can be removed from the oven, otherwise allow the cake to bake for a further 10-15 minutes.

Allow the cake to cool within the loaf tin on a cooling rack. Once the cake is completely cool, wrap in greaseproof paper and place in an airtight tin. Eat within 3-5 days.

This cake can be frozen for up to three months. If freezing, wrap in greaseproof paper, as above, then wrap in foil. Allow to defrost at room temperature for 6 hours or overnight. Freezing can cause the crumble topping to become a little soggy, so consider placing in a loaf tin and returning to a 180°C / 350°F oven for 10 minutes to revive, then allow to cool before serving.

rhubarb crumble cake 4

Printable PDF: Rhubarb Crumble Cake

4 thoughts on “Rhubarb Crumble Cake

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