Rhubarb Crumble Bars

Serves 16 squares 7 May 2020 Vegetarian Friendly
For our next date, let’s make an all time favourite of mine, CRUMBLE BARS. A cinch to assemble these tart, buttery, crumbly yet crisp based squares of deliciousness tick all the boxes of comforting treat to satiate that desire for a little something sweet at any time of the day.

Thank you so much to everyone who has joined the BAKE & DONATE sessions over the past two weeks from literally all over the world and baked along both in real time and in your own time.  I have absolutely loved seeing the incredible cakes and blondies you produced and I am sure you have made people’s day by sharing all the delicious treats.

Your amazing support and feedback have been so incredibly encouraging that I have decided to make this a regular MONDAY BAKE DATE.

As rhubarb has just come into season and is quite readily available, Monday’s bars will be filled with my version of a rhubarb and custard mixture. There are variations for other fillings in the recipe details below my signature, so that like me, you can make a variation of these all year around with whatever you have available in your fridge, freezer or larder.


These these are essentially a crumble in a bar….AKA the dream for any rhubarb lover like me. There is no need to pre-bake the filling or the base in this recipe – simply binding the rhubarb with an egg and some sugar absorbs all the juices and ensures a crisp base.

This is not the first or only iteration of Crumble Bars. Finding their way into the kitchen many years ago as a use for leftover cranberry sauce after a Thanksgiving feast, the base is used throughout the year and filled with anything from a glut of fresh or frozen berries tossed with a little sugar and lemon zest, as an emergency treat with a favourite jar of jam or with compote or apple sauce lurking in the fridge.

I also use this recipe to use up ends of flour hanging around in the baking drawer. Feel free to use a half/half mixture of plain and wholemeal flour or adding white or wholemeal spelt flour into the party gives wonderful nutty flavour undertones. Just use any combination you have on hand. 

I use a 20cm (8 inch) square baking tin for these, but as you are cutting them in to squares, they also work well in an equivalent size oblong tin or high sided baking sheet . If you are using a larger tin, for example a 20×30 cm sheet pan, increase the ingredient amounts in the recipe by one and a half times so that there is enough crumble and filling for a good base and top. 

Crumble Base and Top

  • 175g (1 3/4 cup) unsalted butter
  • 180g (1 1/2 cups) plain flour (or a mixture of plain and wholemeal, wheat or spelt flours)
  • 125g (just short of 3/4 cup) soft brown sugar
  • 150g (1 1/2 cups) jumbo porridge oats (not instant cook oats)
  • 50g (1/2 cup) sliced almonds (optional)
  • 1 tsp ground cinnamon
  • pinch salt

Rhubarb Filling

  • 1 large egg at room temp
  • 150g (3/4 cup) caster (granulated) sugar
  • 30g (2 tbsp) plain flour
  • pinch of salt
  • 1 tsp vanilla extract
  • zest of an unwaxed lemon (or orange when using forced rhubarb in autumn/winter)
  • 400g – approx 5 long stems (3 cups) sliced rhubarb (1cm, 1/4inch thick)

Preheat oven to 180C (350F)

Make the base and top:

Start by melting the butter. Allow it to cool slightly.

Grease and line a 20cm square baking tin with parchment paper and set aside

  • In a medium / large mixing bowl, combine flour, sugar, cinnamon, salt, oats and half the sliced almonds.
  • Add butter and mix together, keeping the mixture loose like a crumble topping.
  • Make the rhubarb filling:
  • Slice the rhubarb stalks into 1 cm pieces
  • In the bottom of your second mixing bowl, whisk to gather the egg and sugar, adding in the flour, lemon zest and vanilla.  Give it another mix to fully combine.  
  • Add the sliced rhubarb and mix with a spatula or wooden spoon to fully coat all the pieces.
  • To assemble:
  • Tip 2/3 of the crumble mixture into the prepared tin and press down into an even layer with the heel of your hand to make the base of the bars.
  • Spread the rhubarb mixture evenly over the base.
  • Loosely shower the rhubarb with the remaining crumble mixture to make a crumb topping.
  • Sprinkle over the rest of the almonds (if using) and pop into the oven 45 minutes until golden. 
  • Allow to cool completely before cutting into bars




Have you made this dish?

Let me know what you think, share your efforts and any tweaks you made to the recipe on Instagram, don’t forget to tag #BuildingFeasts or email me on info@buildingfeasts.com