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Vegan Strawberry Rhubarb Crumble Cake

Vegan vanilla cake layers with strawberry rhubarb filling, walnut pecan oat crumble and strawberry rhubarb vanilla buttercream. 
Course: Dessert
Cuisine: Vegan
Keyword: strawberry rhubarb, summer cake,, vegan buttercream


  • 6 inch cake pan x 3 (could try two 7 inch pans)
  • stand mixer
  • Rotating Cake Decorating Stand
  • Piping Bag


Vanilla Cake

  • 1 cup oat milk
  • 1 tsp apple cider vinegar
  • 2 cups all purpose flour
  • 2 tsp baking powder
  • 1/2 tsp baking soda
  • 1/4 tsp sea salt
  • 3/4 cup granulated sugar
  • 1/3 cup vegetable oil
  • 2 tsp vanilla extract

Strawberry Rhubarb Compote

  • 3 cups strawberries hulled and halved
  • 1 cup rhubarb sliced,
  • 1/4 cup granulated sugar
  • 1 tsp vanilla extract


  • 2/3 cup rolled oats
  • 1 cup all purpose flour
  • 2/3 cup brown sugar
  • 1/2 tsp cinnamon
  • 1/4 cup walnut coarsely chopped
  • 1/4 cup pecan coarsely chopped
  • 1/4 cup maple syrup
  • 1/3 cup vegan butter


  • 225 grams vegan butter
  • 225 grams vegetable shortening
  • 4 cup icing sugar
  • 1 tbsp vanilla extract
  • 3 tbsp strawberry rhubarb compote liquid (not chunks of fruit)


Vanilla Cake

  • Preheat your oven to 375 degrees Fahrenheit.
  • Prepare cake pans by oiling generously and dust an even, light coating of flour and set aside. This keeps the cakes from sticking. I used three 6 inch cake pans for this cake.
  • In a medium sized bowl combine the soy milk and apple cider vinegar, mix and set aside for 5-10 minutes.
  • In a large bowl, sift together flour, baking powder, baking soda, and salt. Stir to combine.
  • Back to the soy milk mixture add sugar, vegetable oil and vanilla extract. Wisk together to combine fully.
  • Pour the liquid ingredients into the dry ingredients and fold in with a spatula. Mix until combined, scraping the sides to ensure you have incorporated everything.
  • Divide the batter evenly between cake pans. Spread across pan with a spatula and tap the pans against the counter to let out any air bubbles.
  • Evenly place the cake pans in your oven and bake for 20 minutes (depending on your oven!) To be safe, you can check the cakes around 18 minutes - insert a toothpick into the centre of the cake and if it comes out clean your cakes are ready to come out of the oven.
  • Place cake pans on a wire rack to cool for 10 minutes. After the 10 minutes you can remove the cake from the pans and leave to cool on the wire rack until completely cooled.
  • Once cooled, level the tops (if needed) and trim off the sides.
  • If planning on assembling the cake another day wrap each cake layer with plastic wrap and chill in the freezer. The cake layers can be stored in the freezer wrapped in plastic for a few days. If you want to store longer, wrap layers in foil and seal in a zip-lock bag.

Strawberry Rhubarb Compote

  • Combine the strawberries, rhubarb, sugar and vanilla over medium heat in a medium saucepan. Bring to a boil.
  • Once the mixture is boiling, reduce the heat to low and let simmer, stirring occasionally. Cook until the fruit is tender and broken down.
  • Let mixture cool completely before using in the cake. I made this the day before and stored in the fridge in an airtight container. This can be stored in the fridge for about a week.


  • Preheat your oven to 375 degrees Fahrenheit.
  • Line a baking sheet with parchment paper and set aside.
  • Combine the rolled oats, flour, sugar, walnuts and pecans cinnamon, and salt in a medium sized bowl and whisk to blend.
  • Add the maple syrup and stir.
  • Crumble the butter into the mixture and mix together (may have to use hands). The mixture should form small clumps. The mixture will stick together like clumps.
  • Spread onto baking sheet and bake for 15 minutes, stirring halfway through.
  • Let cool completely before using in the cake, you can break up the crumble to smaller bits if needed. I baked this the night before assembling the cake. Can be stored in an airtight container.

Strawberry Rhubarb Buttercream

  • Using the paddle attachment add the vegan butter and vegetable shortening to the stand mixer bowl and mix on medium speed for 3-5 minutes until the mixture is light and fluffy.
  • Turn off mixer and sift in one cup of powdered icing sugar. Mix on low speed until combined and repeat with remaining cups of powdered sugar.
  • With the mixer on medium, add vanilla extract and one tbsp at a time of liquid from strawberry rhubarb compote. Beat for 3-5 minutes.
  • Give the frosting a mix by hand with a spatula before frosting your cake!


  • Place cake board on a revolving decorating stand and spread a thin layer of buttercream on cake board. Place the first cake layer on top, top side up (crumb side up).
  • Spread a thin layer of frosting over the cake layer and pipe a ridge along the edge of the cake to hold in the filling. You may need to add more after you add the filling to reinforce the barrier.
  • Spread approx. 1/3 cup of strawberry rhubarb compote on cake layer.
  • Add approx. 1/4 cup crumble to over the strawberry rhubarb compote.
  • Gently place the second cake layer on top of the filling and crumble, crumb side up and repeat steps 2-4.
  • Place the final cake layer top side down on the second layer of filling. 
  • Chill the cake in the fridge for 30 minutes or freezer for 10 minutes to help the cake become more stable before frosting.
  • When the cake feels set it's time for a crumb coat. Apply a small amount of frosting around the entire cake (doesn't need to be perfect, you're looking to lock in the crumbs).
  • Chill the cake in the fridge for 30 minutes or freezer for 10 to set the crumb coat.
  • Remove from fridge/freezer and continue to frost and decorate the cake as you choose.


This recipe will make extra compote, crumble and buttercream. I opted to serve with an additional scoop of the filling and crumble with each slice of cake. You can also repurpose the extras for cupcakes or save in the fridge. The compote and crumble make great adds for oatmeal.