Easy Sourdough Rhubarb Coffee Cake Recipe
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My easy Sourdough Rhubarb Cake Recipe is a sweet treat that puts fresh rhubarb and extra starter to good use. Pieces of rhubarb are folded into a cake batter with a wonderful flavor and baked in a baking dish until golden with a crumb topping of brown sugar and cinnamon.
This sourdough coffee cake is a great recipe to enjoy during rhubarb season and is one of my favorite sourdough discard recipes. If you love rhubarb recipes, try my Sourdough Rhubarb Quick Bread or my Strawberry Rhubarb Pie with a Sourdough Crust.
Quick Look: Sourdough Rhubarb Cake
- Prep Time: 20 minutes
- Cook Time: 40 minutes
- Total Time: 1 hour
- Servings: 16 slices
- Calories: ~207 kcal per slice (based on nutrition panel)
- Cook Method: Baked
- Flavor Profile: Soft, moist, and spongy with tart bites of rhubarb throughout and a sweet, crunchy cinnamon sugar topping. Perfect for breakfast, a snack, or dessert!
- Difficulty: Easy — Simple to mix with a stand mixer and ready in just 1 hour!
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Why You’ll Love This Sourdough Rhubarb Cake Recipe
- Sweet, tart, and perfectly balanced: Each bite delivers a combination of rhubarb tartness and sweet vanilla cake, finished with a crunchy crumb topping of cup sugar and cinnamon. The tart rhubarb brings perfect balance so the cake is never overly sweet. Serve with a scoop of vanilla ice cream or a sprinkle of powdered sugar for a delicious recipe the whole family will love.
- Incredibly moist and gets better the next day: Adding sourdough discard to the cake batter slows gluten formation, giving you the lightest and most moist cake with an airy crumb. The acidity of the discard also reacts with the baking soda, helping it rise beautifully. This cake actually gets more moist the next day, making it the perfect way to bake ahead for guests. For another cake that uses discard, try my Sourdough Apple Cake.
- Quick, easy, and uses simple ingredients: This is basically a dump, mix, and bake recipe. Cream the butter and white sugar in a bowl of a stand mixer (or hand mixer), alternate adding the dry ingredients and wet ingredients, fold in the bits of rhubarb, and bake. No fuss, no confusing steps.
Ingredients & Substitutions
* To find precise measurements, scroll to the bottom of this post to find the recipe card*
Batter
- Sugar – Granulated white sugar sweetens the cake and helps create a tender crumb.
- Egg – One large egg adds structure and richness to the batter.
- Vanilla Extract – Just a teaspoon adds a warm, subtle sweetness that complements the tart rhubarb beautifully.
- Milk – Whole milk keeps the batter smooth and adds moisture to the cake.
- Sourdough Starter – Use unfed sourdough discard straight from the fridge. The acidity slows gluten development, giving you that light, moist crumb. Active starter works too — just use the same amount in grams.
- All-Purpose Flour – Spoon and sift for the most accurate measurement. This gives the cake its structure without making it dense.
- Baking Soda – Reacts with the acidity of the sourdough discard to help the cake rise beautifully.
- Fresh Rhubarb – Chopped into ½-inch pieces, fresh rhubarb is ideal. Frozen rhubarb works just as well — no need to thaw before folding it in!
Crumb Topping
- Sugar – Granulated sugar creates that signature crunchy, golden crust on top.
- Cinnamon – Just a half teaspoon adds a warm spice that ties the whole cake together.
How to Make Sourdough Rhubarb Cake:
- Preheat oven to 350 degrees F.
- Either grease or line a 9×13 baking dish with parchment paper. This is optional, but I love how easily removing the cake is with parchment paper. I can lift it and cut the cake into even squares perfectly, but you choose.
- Chop rhubarb into 1/2-inch pieces, bite-sized. Place them in a small bowl and set them to the side.
- Whisk the discard, milk, and vanilla in a small bowl until combined. Set to the side. In a bowl of a stand mixer with a paddle attachment cream the butter and sugar for about 2 minutes
- In a medium bowl, whisk together the flour and baking soda. Alternate adding the dry ingredients and wet ingredients. Add about a third of the flour mixture, then half of the liquids. Repeat until all of the ingredients have been added and the flour bits have just disappeared. (Note that the batter is on the thicker side) Be sure to not overmix the cake batter – this can lead to a tough crumb.
- Lastly, fold in the bits of rhubarb.
- Pour the batter into the baking dish. Feel free to top it with more pieces of rhubarb if you’d like!
- In a separate bowl, mix together the sugar and cinnamon. Sprinkle on top of the batter – make sure to get all the edges of the cake. Bake in the oven for 40-45 minutes or until a toothpick comes out clean.
- Let the cake cool on a wire rack before slicing and enjoy!
McKenna’s Helpful Tips
- Chop rhubarb into 1/2-inch pieces for even distribution throughout the cake. Smaller, bite-sized pieces of rhubarb bake down into jammy pockets without weighing the batter down. I use the same approach for my Sourdough Blueberry Buckle.
- Line your baking dish or cake pan with parchment paper for easy removal. I love being able to lift the entire cake out and cut it into even squares. Let the cake cool on a wire rack before slicing. This same trick works perfectly for my Sourdough Coffee Cake.
- Do not overmix the cake batter once the flour mixture is added. Alternate adding the dry ingredients and wet ingredients in batches and stir just until combined. Overmixing develops too much gluten and can lead to a tough crumb. I follow this same rule for my Sourdough Banana Bars.
- Make sure your crumb topping covers all the edges of the cake batter before baking. The brown sugar and cinnamon mixture caramelizes in the oven and creates a delicate, crunchy crust on top of the batter. I love a similar topping on my Sourdough Pumpkin Coffee Cake.
- Use a cake tester or toothpick to check doneness at 40 minutes. If it comes out clean, the cake is ready. If not, continue baking in 5-minute intervals up to 45 minutes total. I always check my Blueberry Lemon Poppy Seed Sourdough Muffins the same way.
How to Store
Store any leftover cake in an airtight container at room temperature for up to 3 days.
It also freezes really well! Wrap slices of cooled cake with plastic wrap and store in a ziplock bag for up to 3 months. Thaw on the countertop until room temperature.
Sourdough Rhubarb Cake FAQs
Yes! You can use active sourdough starter, just be sure to use the same amount in grams. You can also long-ferment the batter. After you mix the batter (before you fold in the rhubarb), cover and store the batter in the fridge overnight. The following day, fold in the rhubarb and bake. Since the batter is cold, you might need to add a few minutes to the bake time. For another great recipe using sourdough discard, try my Sourdough Oatmeal Quick Bread.
Absolutely! No need to thaw the rhubarb. Just fold in the frozen slices of rhubarb right before baking. Frozen rhubarb may release a bit more moisture during baking, so check with a cake tester at 40 minutes and add a few extra minutes if needed. My Strawberry Rhubarb Pie with a Sourdough Crust also works beautifully with frozen fruit.
Store any leftover cake in an airtight container at room temperature for up to 3 days. It also freezes really well! Wrap slices of cooled cake with plastic wrap and store in a ziplock bag for up to 3 months. Thaw on the countertop until room temperature. My Sourdough Rhubarb Quick Bread stores the same way.
Rhubarb season in most areas is from April to June. It is one of the first veggies of the season and it is quite bountiful! You can find fresh rhubarb at farmers markets, grocery stores, or right from your own rhubarb plants in the garden. Stock up during rhubarb season and freeze chopped pieces so you can bake rhubarb recipes year-round, like my Sourdough Blueberry Buckle.
If you tried this Sourdough Rhubarb Cake recipe or any other recipe on my blog, please leave a 🌟 star rating and let me know how it went in the📝 comments below. Thanks for visiting!
Sourdough Rhubarb Cake Recipe
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Ingredients
Cake Batter
- 240 grams rhubarb, 1/2 inch slices 2 cups
- 120 grams milk 1/2 cup
- 240 grams sourdough discard 1 cup
- 4 grams vanilla extract 1 teaspoon
- 113 grams unsalted butter, room temperature 1/2 cup
- 350 grams sugar 1 1/2 cups
- 1 large egg
- 150 grams all-purpose flour, sifted spooned and sifted (150g) 1 cup + 1 Tablespoon
- 6 grams baking soda 1 teaspoon
- 3 grams salt 1/2 teaspoon
Topping
- 50 grams sugar 1/4 cup
- 1 gram ground cinnamon 1/2 teaspoon
Instructions
- Preheat oven to 350 degrees F and grease or line a 9×13 baking dish with parchment paper. Set aside.
Mix
- Whisk the milk, sourdough discard and vanilla in a small bowl until combined. Set to the side.120 grams milk, 240 grams sourdough discard, 4 grams vanilla extract
- In a bowl of a stand mixer with a paddle attachment, cream the butter and sugar for about 2 minutes.113 grams unsalted butter, room temperature, 350 grams sugar
- Add the egg to the sugar mixture and beat until fluffy with a pale yellow color, for about 3 minutes.1 large egg
Dry Ingredients
- In a medium bowl, whisk together the flour, baking soda and salt.150 grams all-purpose flour, sifted, 6 grams baking soda, 3 grams salt
- Alternate adding the dry ingredients and wet ingredients. Add about a third of the flour mixture, then half of the liquids. Repeat until all of the ingredients have been added and the flour bits have just disappeared. (Note that the batter is on the thicker side)Be sure to not overmix the cake batter – this can lead to a tough crumb.
- Lastly, fold in the bits of rhubarb.240 grams rhubarb, 1/2 inch slices
Bake
- Pour the batter into the baking dish. You can even top it with more pieces of rhubarb.
- In a separate bowl, mix together the sugar and cinnamon. Sprinkle on top of the batter – make sure to get all the edges of the cake.50 grams sugar, 1 gram ground cinnamon
- Bake for 40-45 minutes or until a toothpick comes out clean.
- Let the cake cool on a wire rack before slicing and enjoy!
Delicious as a cake! But take my advice and don’t attempt to use this recipe to make muffins. I’ll still eat them but, wow, ugliest muffins I’ve ever made. Overflowed, stuck to top of muffin tin, craters and holes in them. Just keep it as is and make a cake! It’s a great cake recipe-uses a good amount of both discard and rhubarb!
Thank you so much for the review and for the warning about the muffins, haha! I’m so glad you enjoyed the cake!
Is is all made with granulated sugar? It just says sugar but it looks like brown sugar in the picture.
That’s correct! The topping is a mixture of granulated sugar and ground cinnamon.
Do you have a sourdough rhubarb bread recipe
I do – Sourdough Rhubarb Quick Bread! Hope you love it!
Would there be a way you could use active starter and do a long ferment?
You can use active starter, just be sure to use the same amount in grams. You can also long-ferment the batter! After you mixed the batter (before you fold in the rhubarb) cover and store the batter in the fridge overnight. The following day, fold in the rhubarb and bake. Since the batter is cold, you might need to add a few minutes to the bake time. If you give this a go, let me know how it turns out!
Have you ever substituted the sugar for honey or maple syrup?
Hi Fran! I personally have not, sorry! If you give it a try, please let me know how it goes!
This cake was delicious nice soft moist cake , with delicious pockets of rhubarb. I used brown sugar and extra cinnamon in the topping. My family really enjoyed this cake!
So glad everyone enjoyed it, Jan!
I’m currently making my second cake and gonna freeze it to enjoy later on! This recipe is definitely a staple, thank you so much 😀
Love this! Thank you for sharing.
Fabulous! Eating it still warm with vanilla ice cream! Great recipe I will save and repeat. Love the use of a cup of discard. I added a rounded tsp of cinnamon to the batter plus topped it with the cinnamon sugar and more rhubarb. We give 10 stars ⭐️ ⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️⭐️
Yay!! Thank you for sharing!
Delicious, light, a perfect coffee cake. We love Rhubarb
So glad you loved it!
Always fun to see new recipes using rhubarb! Thanks!
I love Rhubarb desserts and this one sounds amazing!
It really is delicious!
This looks absolutely amazing! Thank you for sharing!
My pleasure 🙂
I enjoy pretty much anything with rhubarb in it, so I’ll definitely have to try this. Also, side note: your backsplash is really pretty!
Thanks for sharing this recipe!
You and I both! Hope you enjoy it 🙂 And thank you, we got it from Menards, I believe!
I have never tried rhubarb cake but they sounds absolutely delicious!