Strawberry Rhubarb Crumble Slices

Delicious vegan crumble slices full of the flavours of summer! With a more-ish homemade custard filling alongside fresh strawberries and rhubarb and a wonderful oat & coconut crumble.

For July I really wanted to share another summery recipe with you all that also uses seasonal ingredients. Strawberry and rhubarb are simply such a classic combination – and a good one if you ask me – that I simply had to go with this flavour combo!

These crumble slices are super easy to make using whole foods ingredients, such as rolled oats, nuts and coconut flour and it’s only sweetened with maple syrup or coconut nectar (you can use either in this recipe!). I’ve definitely had a big phase of baking crumble slices almost weekly and this strawberry rhubarb version definitely has the potential to become addictive – it’s that good! 

Oh, and have I mentioned yet that it’s filled with homemade vanilla custard? Yes, it does get even better! But let me not tell you the entire recipe in this paragraph already – find the full recipe below! I hope you enjoy it just as much as I did 🙂 

Gluten-Free? No problem – use gluten-free oats in this recipe and you’re good to go!


This recipe is:

  • 100% vegan
  • simply delicious
  • easy to make
  • full of flavour
  • wonderfully fruity
  • creamy
  • more-ish
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Strawberry Rhubarb Crumble Slices

  • Author: romylondonuk
  • Prep Time: 25
  • Cook Time: 35
  • Total Time: 1 hour
  • Yield: 8-12 slices 1x
  • Category: Crumble
  • Method: Baked
  • Cuisine: British
  • Diet: Vegan


Delicious vegan crumble slices full of the flavours of summer! With a more-ish homemade custard filling alongside fresh strawberries and rhubarb and a wonderful oat & coconut crumble.



For the base:

  • 200g oats
  • 60g coconut flour
  • 60ml melted coconut oil
  • 60ml maple syrup or coconut nectar
  • 1 tsp cinnamon
  • 23 tbsp plant milk

For the filling:

  • 200g fresh rhubarb
  • 150g fresh strawberries, stems removed and sliced or roughly chopped
  • 1 tin full-fat coconut milk (400ml)
  • 3 tbsp maple syrup or coconut nectar
  • 1/2 tsp vanilla powder or 2 tsp vanilla extract
  • 34 tbsp cornflour

For the crumble topping:

  • 120g oats
  • 1 tsp cinnamon
  • 20g roughly chopped pecan nuts
  • 35ml maple syrup or coconut nectar
  • 30ml melted coconut oil


  1. Let’s start by prepping the recipe! To get everything done in a timely manner, first chop up your washed rhubarb into roughly 1-inch pieces. Place them in a large skillet or saucepan, fill the bottom to about 1 cm or 1/2 inch with water and cook your rhubarb for 15-20 minutes until softened and the water has evaporated.
  2. In the meantime, prepare your crumble base! In a large mixing bowl, combine the oats, coconut flour, coconut oil, maple syrup, and cinnamon. Stir in 2 tbsp of plant milk, then set the mix aside for 5 minutes. The mixture should be sticky and firm, but not dry and crumbly, so if needed, stir in a little more plant milk.
  3. Grease and line a 20 x 30 cm (8 x 12 in) rectangular cake tin and preheat your oven to 180C (356F). Press the oat mixture firmly into the bottom of the cake tin to create your base.
  4. In a medium-size saucepan, whisk together the coconut milk, maple syrup, and vanilla powder until well combined, then thoroughly whisk in the cornflour and cook over low/medium heat until the custard mixture thickens. By this time your rhubarb should be done also.
  5. Spread out the rhubarb mix evenly on your oat base, then top with the strawberries and cover everything in the custard mix.
  6. In a small bowl, combine the oats for the crumble topping with the cinnamon, pecan nuts, maple syrup and coconut oil and sprinkle the mix on top of the custard layer. Transfer the cake tin to the preheated oven and bake at 190C for roughly 25 minutes or until golden on the top. Remove the cake tin from the oven and allow for the custard slices to cool down at room temperature for about one hour, then carefully transfer them to the fridge for a minimum of 4 hours before slicing and serving.
  7. To decorate, add some fresh strawberries on top and serve with some vegan ice cream or cream.


Swap out the coconut flour for almond flour, if that’s up your street!

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