Old-Fashioned Rhubarb Cake with Brown Sugar Streusel
This tender, old-fashioned rhubarb cake is loaded with tart rhubarb and topped with a buttery brown sugar streusel that bakes up golden and irresistible. The perfect way to use fresh spring rhubarb!
The Rhubarb Cake That Tastes Like Grandma's Kitchen
If you have ever stood at a farmers market staring at a bundle of rosy rhubarb stalks and thought, I need to do something special with this, this is the recipe you have been waiting for. This old-fashioned rhubarb cake is soft and buttery at its core, perfectly tart from generous chunks of fresh rhubarb, and crowned with a brown sugar streusel that bakes into something gloriously crunchy and caramel-kissed.
It is the kind of cake that makes the whole house smell incredible while it bakes. The kind you slice while it is still slightly warm and eat straight from the pan with a fork, no plate required.
Why You Will Love This Recipe
Rhubarb has a reputation for being tricky or overly sour, but this cake genuinely proves otherwise. Here is what makes it work so well:
- The buttermilk keeps the crumb tender and moist without making it dense
- The cinnamon ties the tartness of the rhubarb to the warmth of the brown sugar beautifully
- The streusel topping adds texture and sweetness without being overpowering
- It is a one-bowl batter (almost) that comes together in under 20 minutes
Whether you are making this for a spring brunch, a bake sale, or just because rhubarb season is fleeting and you refuse to waste a single stalk, this cake delivers every single time.
Using the right pan matters more than you might think for a cake like this. A light-colored metal baking pan ensures even browning on the bottom and sides without over-baking the edges before the center sets. A hand mixer also makes the creaming step much easier and gives you better volume.
Tools & Ingredients We Recommend
A Few Tips Before You Start
Chef's Tip: Do not overmix the batter once you add the flour. A few streaks are fine before you fold in the rhubarb. Overmixing develops gluten and can make the cake tough instead of tender.
The streusel is best made first and chilled while you prepare the batter. Cold butter in the streusel means those clumps hold their shape on top of the batter rather than melting into it before the oven sets them.
If your rhubarb stalks are very thick, halve them lengthwise before chopping so the pieces are roughly uniform. This ensures every bite has a good ratio of cake to fruit rather than an occasional overwhelming pocket of tartness.
What to Serve With Rhubarb Cake
This cake is honestly wonderful all on its own, but if you want to dress it up a little:
- A dollop of freshly whipped cream melting into a warm slice is borderline perfect
- Vanilla ice cream turns a casual dessert into something that feels like a restaurant-worthy plate
- For breakfast or brunch, serve it with Greek yogurt and a drizzle of honey
The tartness of the rhubarb cuts through any richness beautifully, so do not be shy about the cream.
Ready to bake? Here is everything you need laid out in one place:
Old-Fashioned Rhubarb Cake with Brown Sugar Streusel
This tender, old-fashioned rhubarb cake is loaded with tart rhubarb and topped with a buttery brown sugar streusel that bakes up golden and irresistible. The perfect way to use fresh spring rhubarb!
Ingredients
- 2 cups all-purpose flour, spooned and leveled
- 1 tsp baking soda
- 1/2 tsp salt
- 1 tsp ground cinnamon
- 1/2 cup unsalted butter, softened to room temperature
- 1 cup granulated sugar
- 1 large egg, room temperature
- 1 tsp vanilla extract, pure
- 1 cup buttermilk, room temperature
- 2 1/2 cups fresh rhubarb, trimmed and cut into 0.5-inch pieces
- 1/2 cup packed brown sugar, for streusel topping
- 3/8 cup all-purpose flour, for streusel topping
- 3 tbsp cold unsalted butter, cubed, for streusel topping
- 1/2 tsp ground cinnamon, for streusel topping
Instruction
Preheat your oven to 350 degrees F (175 degrees C). Grease a 9x9-inch square baking pan and set aside.
Make the streusel topping: In a small bowl, combine the brown sugar, 1/3 cup flour, cold cubed butter, and 1/2 tsp cinnamon. Use your fingertips to rub the butter into the dry ingredients until the mixture resembles coarse, clumpy crumbs. Refrigerate until needed.
In a medium bowl, whisk together the 2 cups of flour, baking soda, salt, and 1 tsp cinnamon. Set aside.
In a large bowl, beat the softened butter and granulated sugar together with a hand mixer on medium speed for 2 to 3 minutes, until light and fluffy.
Add the egg and vanilla extract to the butter mixture and beat until fully combined, scraping down the sides of the bowl as needed.
Reduce the mixer speed to low. Add the flour mixture in three additions, alternating with the buttermilk in two additions, beginning and ending with the flour mixture. Mix just until combined after each addition.
Fold in the chopped rhubarb gently with a rubber spatula until evenly distributed throughout the batter.
Pour the batter into the prepared pan and spread it into an even layer. Scatter the chilled streusel evenly over the top.
Bake for 40 to 45 minutes, or until a toothpick inserted into the center comes out clean and the streusel is deep golden brown.
Let the cake cool in the pan on a wire rack for at least 20 minutes before slicing and serving.
Equipment
- 9x9-inch square baking pan
- Large mixing bowl
- Medium mixing bowl
- Small mixing bowl
- Hand mixer or stand mixer
- Rubber spatula
- Whisk
- Wire cooling rack
Notes
Storing and Freezing
This cake keeps well, which is part of what makes it so practical. At room temperature, loosely covered, it stays fresh for two days. In the refrigerator it holds for up to five days, and individual slices freeze beautifully for up to two months.
If you are planning to freeze slices, wrap each one tightly in plastic wrap and then foil before freezing. Thaw overnight in the refrigerator and warm briefly in the microwave before serving.
Storage Note: The streusel topping will soften slightly after the first day as moisture from the cake migrates upward. It loses a little crunch but none of its incredible flavor.
Rhubarb season is short. Make the most of it.
