Grandma’s Rhubarb Cake Recipe

Spring means rhubarb season, and there’s no better way to celebrate those gorgeous red stalks than with this incredibly moist, tender old-fashioned rhubarb cake! This isn’t just any rhubarb cake. It’s the perfect balance of sweet and tart with a delightfully crumbly cinnamon-sugar topping that’ll have you coming back for seconds (and thirds). Whether you’re dealing with a rhubarb windfall from your garden or just picked up some beautiful stalks at the farmer’s market, this easy one-bowl cake is exactly what you need to transform that tart rhubarb into something absolutely irresistible.

This one’s for you mom! This family-favorite rhubarb recipe is a must-try for the rhubarb lover. My mom and aunties make this cake every spring to bring to friends, to share at potlucks, for church bake sales, and as an easy and delicious way to use their bumper crop of rhubarb that always seems to grow abundantly in their gardens. This year they were all making it within a few days of each other and texting pictures back and forth (it was adorable). So, basically, this cake is A THING in our family.

As someone who’s spent countless hours in Midwestern kitchens learning from the best home bakers, and several who are rhubarb enthusiasts, I know what makes a truly great rhubarb cake. This recipe delivers every single time. It’s reliable, uses simple pantry staples, and creates that perfect tender crumb that soaks up all those delicious rhubarb juices without getting soggy. Whenever our family shares this cake, the feedback is always the same: “This is THE rhubarb cake recipe I’ve been searching for!”

If you are looking for more ways to use your rhubarb, try my mom’s rhubarb compote with strawberries and apples too!

Rhubarb Cake Recipe Ingredients

• Fresh rhubarb stalks. These bright red stalks are the star of the show in this easy snack cake recipe! Whether you’ve got rhubarb that’s a deep red, or a mix of pink and green, they’ll work great in this recipe.
• Brown sugar AND granulated sugar. We’re using a combination of sugars to create the perfect texture, depth of flavor, and sweetness in our cake.
• Salted butter. Butter adds richness, flavor, and helps us achieve a softer, more tender crumb.
• Large egg. Using a whole egg not only adds richness, it helps provide structure, and contributes to the final light and fluffy texture of our cake.
• Buttermilk. Grandma’s hand-written recipe officially says ‘”‘sour milk’, which today means buttermilk. This acts as both a leavening agent in our cake, adds some flavor, and makes our cake extra tender. Don’t have buttermilk? No worries! I’ve got notes below for how you can make your own ‘sour milk’.
• Vanilla. Used to enhance the depth of flavor of our cake.
• All-purpose flour. We’re using a standard all-purpose flour, which you likely already have on hand for this recipe. All-purpose flour does have a higher protein content (which correlates to gluten development in baking) than a cake flour does, giving our cake a slightly coarser crumb. But if all-purpose was good enough from Grandma, and all my aunties still use it, it’s good enough for us too!
• Baking soda. Used as our main leavening agent, baking soda helps create a more tender texture.
• Salt. Used as an overall flavor enhancer, balancing out the sweetness levels of our cake.
• A blend of granulated sugar and cinnamon for topping. After our batter is mixed together and transferred to our pan, the perfect blend of cinnamon-sugar is added to the top before baking. This adds a little texture and nice flavor on top of our cake.

Refer to the recipe card at the bottom of the post for measurements and detailed recipe directions.

How To Make Rhubarb Cake

Prep. Preheat your oven to 350°F, grease a 9×9 baking pan and set aside.

Make the batter. In a medium mixing bowl, cream together the butter and sugars.

Add the egg and break apart the yolk, begin to beat it into the butter and sugar mixture.

Add the buttermilk and vanilla extract and stir to combine.

Slowly stir in the dry ingredients until just combined (a few lumps are ok, avoid overmixing for the most tender cake).

Gently fold in the rhubarb pieces and stir to distribute throughout the batter.

Put the batter in the pan. Transfer the batter to the prepared 9×9″ pan.

Spread the batter into an even layer in the cake pan.

Add the cinnamon-sugar topping. Stir the cinnamon and sugar together and sprinkle over the top of the cake.

Bake for 28-32 minutes, until a toothpick inserted into the center comes out clean (a few crumbs are ok).

Cool. Place the cake onto a wire rack and let it to cool for at least 10-minutes (cooling it fully for easiest slicing, about 1-hour). Slice, serve, and enjoy!

Easy Rhubarb Cake Variations

Mix in some different fruits. If desired, replace some of the rhubarb with chopped fruit (like strawberries, cherries, or apples) for a fun twist. Just be sure to cut the pieces a similar size and use about 1 Cup of chopped rhubarb + fruit total to mix in to a single batch of the recipe.

Possible Dietary Restrictions?

This cake is vegetarian as written, but can be made gluten-free easily replacing the all-purpose flour with a 1-to-1 gluten free flour (we like and use Bob’s Red Mill 1-to-1 flour for baking).

How To Store Rhubarb Cake

Allow the cake to cool fully, then either cover it with plastic wrap (or transfer it to an airtight container) and store it at room temperature for up to 3 days or in the fridge for up to 1 week.