This rhubarb coffee cake is one of those simple cakes that has a really nice balance of sweet and tart. The rhubarb softens as it bakes and adds little pockets of flavor throughout the cake. It’s easy to make and works really well for breakfast or a snack when you want something homemade without too much effort.

Why You Will Love This Recipe

This rhubarb coffee cake is great because the texture is soft and the rhubarb adds a fresh, slightly tart flavor that keeps it from being too sweet. The buttermilk helps keep the cake moist, and the crumb topping adds a little texture on top. Another reason I like this rhubarb coffee cake is that it’s simple to make and doesn’t need anything fancy, but still turns out really good every time.

What You Will Need

You will need rhubarb, which is the main ingredient and gives the cake its tart flavor and soft texture once baked.

All-purpose flour is used in both the cake and the topping to give structure. Cornstarch helps keep the crumb soft and tender.

Granulated sugar adds sweetness, while butter adds richness and helps create both the cake texture and the crumb topping.

Buttermilk keeps the cake moist and adds a slight tang that works well with the rhubarb. Egg helps bind everything together.

Vanilla adds extra flavor to the cake, and if you use vanilla paste you may see small flecks throughout.

To help the cake rise you’ll use baking powder, and a little salt balances the sweetness.

For the topping you will mix butter, sugar, flour, and vanilla powder to create a simple crumb layer.

Ingredients

Crumb Topping

• 1/2 cup sugar
• 1/3 cup all purpose flour
• 1 tsp powdered vanilla
• 4 Tbsp cold unsalted butter, cut in small pieces

Cake

• 3/4 cup sugar
• 4 Tbsp unsalted butter, at room temperature
• 1 large egg
• 1 Tbsp vanilla paste or extract
• 1/2 cup cultured buttermilk
• 1 3/4 cups all purpose flour
• 1/4 cup cornstarch
• 1 tsp baking powder
• 1/2 tsp salt
• 3 cups rhubarb, thinly sliced

How to Make Rhubarb Coffee Cake

Start by heating your oven to 360°F and greasing a 9×9 baking pan. You can also line it with parchment paper if you want to lift the cake out easily later.

To make the crumb topping, combine the butter, sugar, flour, and vanilla powder in a bowl. Use your fingers to work the butter into the dry ingredients until the mixture becomes crumbly. Set it aside.

In a bowl whisk together the flour, cornstarch, baking powder, and salt and set this aside.

In a large bowl beat the butter and sugar together until the mixture becomes light and fluffy.

Add the egg and vanilla and mix until everything is combined.

With the mixer on low speed, add half of the flour mixture. Once it’s mostly mixed in, add the buttermilk. Then add the rest of the flour mixture and mix until everything is combined.

Fold in the sliced rhubarb. The batter will be thick.

Spread the batter evenly into the prepared pan, then sprinkle the crumb topping over the surface.

Bake for about 40 minutes, until the top is lightly golden and a toothpick inserted in the center comes out without wet batter.

Let the cake cool for about 10–15 minutes before slicing.

Storage

Store the cake covered at room temperature for a few days, or freeze it for up to 2 months once fully cooled.

More Coffee Cake Recipes

• Sour Cream Coffee Cake 
• Apple Coffee Cake
• Cinnamon Coffee Cake
•  Blueberry Coffee Cake
• Pumpkin Coffee Cake