A soft, buttery cake packed with tart rhubarb and finished with a cinnamon crumble—perfect with morning coffee or a slow afternoon.
This is the kind of cake that doesn’t try too hard. It’s simple, a little rustic, and exactly what you want when rhubarb is in season. The sour cream keeps it tender, the rhubarb brings that sharp bite, and the topping gives just enough sweetness to balance everything out.
🧾 Ingredients
Cake Batter
- ½ cup butter or margarine, softened
- 1½ cups sugar
- 2 eggs
- 1 cup sour cream
- 1 tsp vanilla
- 2 cups flour
- 1 tsp baking soda
- 2 cups rhubarb, finely chopped
Cinnamon Crumble Topping
- ½ cup brown sugar
- 4 tbsp flour
- 1 tsp cinnamon
- 1 tbsp butter, softened
🔪 Instructions
- Preheat & prep
Preheat your oven to 350°F (175°C). Grease a 9×13-inch baking dish (or line it if you’re feeling tidy). - Cream the base
In a large bowl, beat together the butter and sugar until light and fluffy. Don’t rush this part—it sets the tone for the whole cake. - Add eggs & flavour
Beat in the eggs one at a time, then stir in the vanilla and sour cream. The batter will look rich and smooth. - Mix dry ingredients
In a separate bowl, whisk together the flour and baking soda. - Combine gently
Add the dry ingredients into the wet mixture. Stir just until combined—no overmixing. - Fold in rhubarb
Gently fold in the chopped rhubarb. The batter will be thick and slightly lumpy—that’s exactly right. - Spread into pan
Pour the batter into your prepared pan and smooth it out evenly. - Make the crumble
In a small bowl, mix brown sugar, flour, cinnamon, and butter until crumbly. - Top it off
Sprinkle the crumble evenly over the batter. - Bake
Bake for 40–45 minutes, or until a toothpick comes out clean from the centre. - Cool slightly & serve
Let it cool just enough so it holds together, then slice and serve warm or at room temp.
🍽️ Tips for the Best Rhubarb Coffee Cake
- Don’t overmix
Once the flour goes in, keep it gentle. Overworking the batter makes the cake dense instead of soft. - Use fresh rhubarb if you can
Frozen works too—just thaw and drain it well so you don’t water down the batter. - Cut rhubarb small
Finely chopped pieces distribute better and keep every bite balanced. - Want more texture?
Add a handful of chopped walnuts or oats to the crumble topping. - Let it rest before slicing
It firms up slightly as it cools, making cleaner slices (if you can wait that long).
☕ When to Serve It
This isn’t just a “coffee cake”—it’s:
- Breakfast with strong coffee
- A mid-day break cake
- A bring-it-to-the-hall kind of dessert
- Or something you quietly cut a second piece of when no one’s looking
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