Sourdough Rhubarb Coffee Cake – with sourdough discard

This Sourdough Rhubarb Coffee Cake made with fresh rhubarb is delightful! The rhubarb melts into the moist cake, making it extra tender, and the crumb topping adds a perfect crunch. Sweet and tart at the same time, this is one cake that will have you coming back for more. It is the perfect snack for early spring days when you see rhubarb plants popping up in your garden, or walk by juicy red rhubarb stalks at the farmers’ market. It’s a delicious rhubarb dessert to make when rhubarb is in season. 

Why use Sourdough Discard in Rhubarb Cake?

I love including sourdough discard in my recipes. Nothing goes to waste! Adding discard or anything acidic to a cake recipe slows down the formation of gluten. It improves not only the cake’s texture but also adds more lift. The acid of sourdough discard prevents the cake from becoming tough or chewy, resulting in a delicate, melt-in-your-mouth texture. I’m thoroughly convinced! 

You won’t notice the ‘sour taste’ of the sourdough discard you are adding. It only balances out the tart taste of rhubarb with the sweet cake flavor. This sourdough rhubarb coffee cake is a mixture between a crumble cake and coffee cake. The best of both!

 If you love rhubarb recipes, you’ll also enjoy my Rhubarb Breakfast Muffins with sourdough discard.

Why you’ll love this rhubarb cake recipe

Seasonal baking – I love rhubarb season! Baking with local, in-season fruit is good for you and your wallet. Walking out to your garden barefoot, cutting off some rhubarb stalks, and baking an amazing dessert with them is highly therapeutic! Your family and your heart will thank you!

Extremely moist and tender – The sourdough discard and sour cream in this recipe make it a super moist, tender cake. 

Easy and Quick recipe – This is not a recipe with many steps and complicated instructions. You can have it ready to bake in less than 20 minutes. Not bad for a busy mom with many mouths to feed and little time. 

Made with everyday ingredients – Recipes that use everyday pantry ingredients are my favorite. Nothing over the top here. Just simple ingredients that you’ll have on hand, with a rhubarb twist. 

Great way to use up sourdough discard – I’m always on the hunt for recipes that use leftover discard. From Sourdough Rhubarb Muffins to Sourdough Discard Cinnamon Bread, I love the tang and flavor that it adds to ordinary recipes. 

Sourdough Rhubarb Cake Ingredients

Crumble:

All Purpose Flour

Brown Sugar

Cinnamon

Pinch of salt

Melted Butter

Rhubarb Cake Batter:

Butter

Sugar

Egg

Vanilla

Sour Cream

Sourdough Starter Discard

Baking Powder

Baking Soda

Salt

Flour

Chopped Fresh Rhubarb

How to make Sourdough Rhubarb Coffee Cake

Preheat oven to 350 F.

Line the bottom of a springform cake pan with parchment paper. Grease the side of the pan for easy removal and to prevent the cake from sticking to the side. 

Chop the rhubarb into 1/2 inch, bite-sized pieces. Place them into a small bowl and set aside. 

Next, make the crumble. 

Combine all the dry ingredients in a medium bowl. Add the melted butter and mix well with a fork until crumbly. Place into the refrigerator until ready to use. 

Use a hand mixer to beat butter and sugar until light and fluffy in a medium-sized bowl.

Add egg, vanilla, sour cream, and sourdough discard. Mix until combined. 

Next, add baking powder, salt, and baking soda. Add flour. Mix until just combined, and you can’t see any more dry bits of flour. 

Fold in chopped rhubarb. (Note that this batter is on the thicker side) 

Be sure not to overmix the batter; this can lead to a dry, tough crumb. 

Use a spatula to spread the batter into the prepared springform cake pan. 

Remove the crumble from the fridge and top the rhubarb cake batter with the crumble. Be sure to get all the edges of the pan for an even crumble layer. 

Bake in the oven, on the middle rack, for 45 to 50 minutes. The top should be light golden brown. A toothpick should come out clean, and the middle shouldn’t be jiggly.

Let the cake cool before slicing and serving. Enjoy with a dollop of whipped cream or some homemade vanilla ice cream! 

Looking for more sourdough discard snack recipes?

Are you always on the hunt for more sourdough snack recipes? Try my Sourdough Discard Apple Fritters or Sourdough Cinnamon Bread. My kids’ favorite is homemade Sourdough Pop-Tarts with blueberry frosting. So delicious and fun to make! I love making my White Chocolate and Cranberry Sourdough Scones for a Saturday morning breakfast.

How to store Rhubarb Coffee Cake

Store any leftover cake in an airtight container at room temperature for up to 3 days. 

For freezing, wrap in plastic wrap and store in a zip-lock bag or freezer container for up to 3 months. Thaw at room temp. You can put it in the oven to warm up slightly before serving. 

Does it matter if my sourdough discard is too runny?

No! Use any unfed starter. The sweetness of the cake masks the tanginess of the discard. 

Can I use frozen rhubarb?

Yes, you can use frozen rhubarb. Toss the frozen rhubarb with 2 tbsp flour before adding to the cake batter.