Rhubarb Custard Crumble Bars

Rhubarb and Custard Crumble Bars

I had some rhubarb knocking about in my freezer and, almost immediately, all I could think about was rhubarb and custard. There’s something about that classic combination that is just impossible to resist – sharp, sweet, creamy and incredibly comforting.

So, naturally, the rhubarb and custard needed to become a crumble.

And that’s how these rhubarb and custard crumble bars were born.

These easy rhubarb crumble bars combine a buttery shortbread base with a thick, homemade rhubarb custard filling and a golden, crumbly topping. They’re essentially everything I love about a traditional rhubarb crumble and custard, but in delicious little bars that are perfect with a cup of tea.

You can use fresh or frozen rhubarb, so this is also a brilliant recipe if you have some rhubarb tucked away in the freezer.

Why You'll Love These Rhubarb Custard Crumble Bars

• Classic rhubarb and custard flavour

• Perfect for using fresh or frozen rhubarb

• Buttery shortbread base and crumble topping

• Soft, creamy rhubarb custard centre

• Easy to prepare

• Perfect with a cup of tea or coffee

• Delicious served warm or chilled

Ingredients

For the Rhubarb Filling

• 200g rhubarb, sliced – fresh or frozen

• 150g granulated sugar

• A splash of water

For the Custard

• 1 tsp vanilla extract

• 2 tbsp custard powder

• 300ml whole milk

• 1 tbsp granulated sugar

For the Shortbread Base & Crumble Topping

• 400g plain flour

• 150g icing sugar

• 200g salted butter, cubed and cold

• Cold water, as needed

How to Make Rhubarb and Custard Crumble Bars

Preheat your oven to 180°C and line an 8 x 8 inch baking tin with baking paper.

Make the Rhubarb Custard Filling

Start by making the rhubarb filling. Add the sliced rhubarb, granulated sugar and a small splash of water to a saucepan.

Place over a medium-low heat and cook gently, stirring occasionally, until the rhubarb has softened and almost all of the liquid has evaporated.

The important thing here is to make the rhubarb very thick. You want to cook it beyond the consistency of a loose jam because you don't want excess liquid soaking into your shortbread base.

Once the rhubarb is thick, mix the custard powder, vanilla extract, sugar and whole milk together until smooth.

Pour the custard mixture into the saucepan with the cooked rhubarb.

Stir everything together and continue cooking over a medium-low heat, stirring constantly, until the custard becomes extremely thick.

Remove from the heat and set aside while you prepare the shortbread.

Make the Shortbread Base

Add the cold cubed butter, plain flour and icing sugar to a food processor.

Pulse until the butter has been completely incorporated and the mixture resembles fine crumbs.

If you don't have a food processor, you can grate the cold butter into the flour and rub it together with your fingertips before mixing through the icing sugar.

Add approximately 1 tablespoon of cold water and pulse again. Continue adding tiny amounts of water until the mixture just comes together into a dough.

Be careful not to add too much water – you want a crumbly shortbread dough rather than a wet dough.

Assemble the Rhubarb Crumble Bars

Take approximately two-thirds of the shortbread mixture and press it firmly and evenly into your lined 8 x 8 inch baking tin.

Place it into the preheated oven and bake until the edges are just beginning to turn golden. The base doesn't need to be completely baked at this stage as it will go back into the oven later.

Remove the partially baked shortbread base from the oven.

Pour the thick rhubarb and custard filling over the hot base and spread it into an even layer.

Take the remaining third of the shortbread mixture and use your fingers to break it into small pieces.

Scatter the crumble mixture over the top of the rhubarb custard, covering the surface as evenly as possible.

Return the tin to the oven and bake for approximately 25–30 minutes, or until the crumble topping is beautifully golden brown.

Allow the bars to cool before slicing.

How to Serve Rhubarb and Custard Crumble Bars

These rhubarb custard bars are delicious on their own with a cup of tea, but if you want to make them extra indulgent, serve them slightly warm with a scoop of vanilla ice cream.

And if you're a serious rhubarb and custard fan, there's absolutely nothing stopping you from serving them with a little extra warm custard!

Can I Use Frozen Rhubarb?

Absolutely! Frozen rhubarb works really well in this recipe, which is exactly what I used.

You don't necessarily need to defrost it first. Just add the frozen sliced rhubarb directly to the saucepan with the sugar and splash of water and allow it to cook down gently.

The most important thing is to make sure you cook the rhubarb mixture until it is very thick and most of the moisture has evaporated before adding the custard.

Storage

Once cooled, store your rhubarb and custard crumble bars in an airtight container in the refrigerator.

Because of the custard filling, I recommend keeping them chilled and eating them within a few days.

They can be enjoyed cold from the fridge or gently warmed before serving.

A Classic Rhubarb and Custard Dessert in Bar Form

I think rhubarb and custard might be one of the most underrated flavour combinations. The sharpness of the rhubarb against the sweet, creamy vanilla custard is just perfect, especially when it's paired with buttery shortbread and a crisp crumble topping.

These rhubarb and custard crumble bars are a lovely way to use up rhubarb, whether you've got fresh rhubarb from the garden or a bag hiding in the freezer.

They're nostalgic, comforting and incredibly moreish – basically a rhubarb crumble with custard in sliceable bar form.

And honestly, I couldn't think of a better fate for that forgotten bag of rhubarb in my freezer!