Rhubarb Upside Down Cake

Think pineapple upside down cake, but swap that sweet pineapple for tart rhubarb. No need to pre-cook the rhubarb, we’ll trim it thin so it can bake perfectly in the ‘caramel’ topping. 

Recipe Origins 

The cake part of this recipe has roots in my everyday butter cake. I tend to choose this cake because it’s a great canvas for any flavor and can be tweaked for so many uses. In this recipe it is a little denser than EBC, thanks to the weight of the topping an the fact that it’s overturned so a lot of the air gets pressed out (the same thing that happens with any fruit-upside down cake), but it’s still wonderfully buttery and moist. 

My biggest changes were leaving out some of the additional sugar since we’re topping this cake with caramel and flavoring it with cinnamon to complement the rhubarb (you can swap it for lemon if you prefer). The caramel topping is pretty standard to what you’d find in any upside down cake: butter and sugar cooked briefly and spread onto the pan before the fruit. 

And – I’m so happy because I finally found a way to incorporate rhubarb into a recipe where it’s best traits are shown off: gorgeously ruby red stalks that can be arranged into lovely designs!

Recipe Ingredients 

Rhubarb: fresh rhubarb, leaves trimmed. 

Sugar: brown sugar for the ‘caramel’ topping and fine granulated for the cake. 

Cinnamon: ground cinnamon. If you prefer a brighter cake flavor, swap it out with the zest of 2-3 lemons. 

Vanilla: pure vanilla extract or vanilla bean paste. 

Salt: fine sea salt. Use half the amount if using table salt. 

Butter: unsalted. We’re melting it for both parts of the cake so cold is fine. 

Flour: all purpose flour or cake flour. Either will work for the cake although cake flour will give it a lighter crumb. 

Sour cream: full fat sour cream. Can be swapped with greek yogurt if desired. 

How to make Rhubarb Upside Down Cake 

Prep the pan and the rhubarb: grease the pan with a light spray or oil or butter, this will ensure an easy release from the cake pan. 

For the rhubarb, trim the bottoms and leaves off first, then chop into varying sizes for slices that will fit into the bottom of the pan. Slice it down horizontally too so that you have thinner slices of rhubarb. 

Cook the butter & sugar: in a pan add the butter, once it melts, add the sugar and stir until it’s thick and shiny. Pour into the pan and spread into an even layer. 

Arrange the rhubarb: set them, red face down, tightly tucked next to each other. Trim any too long stalks to fit them into the pan (see photos and video for reference). 

Melt the butter & mix with flavorings, then sugar: now we’ll make the cake batter. Melt the butter and mix with the vanilla and salt (and whatever other flavor you like) and then whisk the sugar until thick and shiny. 

Whisk the eggs in, one by one: the eggs MUST be at room temperature or your batter will split. Add one egg then whisk well, then another and whisk. One by one whisking vigorously. 

Whisk in the remaining ingredients: the flour, baking powder and sour cream. Stop once the batter is smooth. 

Spread batter over the rhubarb: Pour the batter over the rhubarb and use an offset spatula to smooth it into an even layer. 

Bake the cake: in a preheated 350 F oven, until a cake tester comes out clean of cake batter. 

Arranging the Fruit for an Upside Down Cake (prepping the rhubarb)

There are so many ways to play with rhubarb stalks (and I can do exactly one of them which is the one you see here ;p) so while I have given instructions for something very basic: slice the stalks horizontally to make them thinner then arrange face down, you can also go for something prettier. One of my favorite rhubarb recipe designs is Thida Bevington’s rhubarb tart, I think you could have a lot of fun trimming and playing around with geometric designs. Just be aware some of the rhubarb (especially the thinner stalks) might sink into the cake a bit. Just like pie, these things are never as pretty as a pre-bake, but always just as delicious!

Storing Upside Down Cakes

Fruit on the bottom (which then ends up on top) cakes can be stored either at room temperature (for about 2 days) or in the fridge (for up to 4 days). In either case I’d keep the cake’s leftovers in an airtight container.

Rhubarb Upside Down Cake Recipe

Upside Down Rhubarb Cake

Moist cinnamon cake with a caramelized rhubarb topping.

Prep Time: 30 minutes mins

Cook Time: 40 minutes mins

Yields: 1 9 inch cake

5 from 3 votes

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Ingredients

Rhubarb Topping

• About 3 stalks rhubarb
• 150g or ¾ cup brown sugar
• 57g or ¼ cup butter

Cinnamon Cake

• 226g or 1 cup unsalted butter
• 200g or 1 cup fine granulated sugar
• ¾ tsp fine sea salt
• 1 teaspoon pure vanilla extract
• 1 teaspoon ground cinnamon OR zest of 2 lemons
• 3 large eggs at room temperature
• 170g or ¾ cups sour cream
• 260g or 2 cups cake or all purpose flour sifted
• 2 teaspoons baking powder

Method

• Grease a 9 inch cake pan.
• Trim the rhubarb to remove the leaves and brown bottoms. Slice the stalks horizontally so that you have thin stalks then slice to varying lengths until you have enough to fit across the bottom of the pan (some will be shorter; the ones that go in the center will be longer).
• In a skillet, add the butter and set over low heat. Once it melts, add the brown sugar and stir until it comes together in a thick, shiny mix.
• Spread the butter mix into the bottom of the prepared pan. Arrange and lay the rhubarb over it so that the redder sides of the stalks are face down, adding enough to cover the entire bottom of the pan. Set aside while you make the cake batter.
• Preheat the oven to 350 F.
• Set the butter in a heatproof bowl and microwave it until it’s mostly melted (but don’t let it sputter or you’ll lose some of the fat needed in the cake).
• Add the vanilla, cinnamon, and salt to the butter and whisk. Add the sugar and whisk very well, for at least a full minute.
• One by one, add the eggs - whisking well after each addition. The mix should be thick and smooth. Add the remaining ingredients (flour, baking powder and sour cream) and whisk to combine.
• Pour the batter over the rhubarb in the pan and smooth out into an even layer.
• Bake the cake for about 40 minutes, until a cake tester inserted into the center (not the rhubarb) comes out clean from batter.
• Let the cake cool briefly (about 10 minutes) in the pan then loosen it with an offset spatula run around the sides. Set a plate over the pan and flip the cake then pat the bottom to make sure you get out all the rhubarb. Lift the pan - it’s ok if some of the sugar/butter mixture got stuck on the edges.
• Serve the cake warm. Store leftovers in the fridge in an airtight container.

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