Rhubarb Upside Down Cake
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Celebrate the season with an easy Rhubarb Upside Down Cake. Baked and unmolded, this cake has a mosaic top of rhubarb baked into a brown sugar sauce over a vanilla, cinnamon cake. It’s utterly delicious and simple to make.

It is the perfect spring dessert. The topping is chopped fresh rhubarb and the cake is a delicious, soft, and tender yet dense cake infused with vanilla, cinnamon, and cardamom, one of my favorite spice combinations.
If you’re not a fan of cardamom, simply leave it out. But for me… the cinnamon belongs with rhubarb!

Rhubarb in the Spring
The rhubarb growing season begins most often in early May and can last into the first few days of July… if you’re lucky.
In the Pacific Northwest, where I am, it has a short season. So when it comes into the market or ripens in my garden, I’m baking and making every recipe I can think of with rhubarb. Even if they’re simple Rhubarb Muffins with streusel topping for brunch!
If you’re looking for a single-layer cake, (not an upside-down cake), you might love my Rhubarb Cake. It’s an old family recipe that we make every early summer.

When Is Rhubarb Ripe?
If you’re growing your own rhubarb, it’s ready to harvest when the stalks are about 10-inches long and the leaves are fully open.
Do remember that the leaves of the rhubarb plant are not edible and should not be eaten.

Rhubarb Upside Down Cake Ingredients
Much like the ingredients in my always popular Plum Cake recipe, the ingredients in this upside-down are delicious and simple. The exact measurements are in the recipe card at the bottom of this post, but gather these ingredients:
- Fresh rhubarb
- Granulated sugar and brown sugar
- Cornstarch
- Unsalted butter
- All-purpose flour
- Baking powder
- Ground cinnamon
- Cardamom (optional but so good!)
- Large eggs
- Vanilla
- Sour Cream
Kitchen Tools Needed to Make Upside Down Cake
Here are the kitchen tools I use to make this cake:
- Stand mixer or handheld mixer to make the batter
- 9-inch springform pan (I prefer nonstick)
- Foil to wrap the pan to keep the juices intact while baking
- Baking sheet

How to Make Rhubarb Upside Down Cake
While this cake is super simple to make, there are 3 distinct parts of the recipe; the rhubarb, a brown sugar sauce that helps make the top of the upside-down cake; and then the actual cake itself.

The rhubarb topping consists of chopped rhubarb, granulated sugar, and cornstarch. This is tossed together and set aside.
A Brown Sugar Sauce is made on the stovetop by melting butter and brown sugar together; whisking until it’s smooth and bubbly.

Finally, the cake batter is made in a stand mixer or with an electric mixer.
To assemble the cake:
Pour the Brown Sugar Sauce into the bottom of the springform pan, then spoon in the rhubarb with its juices over the top. Then spoon in the cake batter so that it covers all of the rhubarb. Smooth the top with a spatula.
Rhubarb Upside Down Cake Questions
In my house– 24 hours tops! I’m kidding, kind of… but truly, the cake can be stored at room temperature for 1 to 2 days. Although if any leftovers remain, you can cover and refrigerate them for up to 3 days.
Absolutely! Assemble the upside-down cake up to the point of baking, wrap securely, and refrigerate for up to 2 days ahead.
This cake freezes well! Wrap securely and freeze for up to 1 month.
If you’re not a fan of rhubarb, you can easily substitute any fruit or berry.

More Rhubarb Recipes You May Also Enjoy
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Rhubarb Upside Down Cake
Ingredients
Rhubarb Topping
- 1 ½ lbs rhubarb cut into 1/2 inch pieces *see notes
- 1/2 cup granulated sugar
- 2 teaspoons cornstarch
Brown Sugar Sauce
- 1/2 cup brown sugar
- 4 tablespoons butter
Upside Down Cake
- 2 cups all-purpose flour
- 1 ½ teaspoons baking powder
- 1 teaspoon cinnamon
- 1/2 teaspoon salt
- 1/4 teaspoon ground cardamom
- 1 cup butter softened to room temperature
- 1 cup sugar + 2 tablespoons divided
- 3 large eggs
- 1 teaspoon vanilla
- 1/3 cup sour cream
Instructions
- Preheat the oven to 325°F. Butter the sides and bottom of a 9-inch springform pan. Wrap 2 layers of foil under the pan and place it on a baking sheet.
- In a medium bowl, add the chopped rhubarb, cornstarch and sugar; toss to combine.
- For the sauce; in a small saucepan over medium heat, whisk together the brown sugar and butter. Continue whisking until the butter is melted and the sauce is smooth and bubbling; about 2 minutes.
- Combine the dry ingredients In a separate bowl, whisking the flour, baking powder, cinnamon, salt, and cardamom.
- With an electric or stand mixer, cream together 1 cup room temperature butter and 1 cup sugar, beating until it is light and fluffy; about 3 minutes. Add the eggs, vanilla, and sour cream to the bowl, and mix on low speed until just combined. Gradually add the flour mixture to the butter mixture and mix until smooth; scrape down the bowl as needed.
- Assemble the Upside Down Cake
- Pour the Brown Sugar Sauce into the bottom of the springform pan, then spoon in the rhubarb with its juices over the top. Then spoon in the cake batter so that it covers all of the rhubarb. Smooth the top with a spatula.
- Bake the Cake
- Bake for 1 hour and 15 minutes, or until the top of the cake is firm and a toothpick inserted in the middle comes out mostly clean.
- Let the cake cool in the pan for 15 minutes then run a knife around the outside edges of the cake. Place a plate on top of the pan and turn it upside down. Then release the cake from the pan while it's still warm, otherwise, it will stick to the pan.
Video
Nutrition
Nutritional information is only an estimate. The accuracy of the nutritional information for any recipe on this site is not guaranteed.
I made this with some strawberries that were past their prime and it was delicious! They were sweet and jammy and the cake was tender and delicious. I halved the cardamom because and it gave it just the right amount of subtle flavor. Yum!
Help! The ingredients say 1/2 c butter for cake but then in directions it says cream 1 cup room temperature butter and 1 cup sugar.
Also, if using frozen rhubarb how many cups would it be if it calls for 1 1/2 lbs fresh?
Thanks in advance,
Mary-Margaret Petrovich
It’s 1 cup of butter – 2 sticks! I’ll make sure that is updated!