last updated on October 30, 2026

If you need a cake that is perfect for spring and summer, this rhubarb upside down cake is the cake for you! We start with an incredibly moist white cake with a hint of grapefruit that makes it fresh and vibrant, all topped with beautiful rhubarb that cooks upside down to perfection. The rhubarb is slightly tart, making it the ideal balance to our white cake!

If you’ve never made an upside down cake, don’t stress! They’re really not that hard but the result is beautiful. You’ve probably heard of pineapple upside down cakes, but I am a much bigger fan of using other fruits like rhubarb or oranges.

why is it called an upside down cake?

It gets the name because after these cakes are baked, they’re flipped upside down served like that! So, we put everything we want to be on top of the cake (when it’s finished) in the bottom of the pan, essentially making it so we bake the cake upside down! Thus the name.

ingredients needed for the rhubarb upside down cake

butter
sugar
grapefruit zest
vanilla
eggs
flour
baking powder
salt
plain greek yogurt
rhubarb

how to make the rhubarb upside down cake

prepping the rhubarb

Wash and dry your rhubarb. I use an 8 inch circle pan when I make this because it’s what I have! This will be easier if you use a square pan, because then you can cut all the rhubarb the same length. So if you have a square pan, it might be the better choice.

Starting with your largest pieces of rhubarb, cut them so they will fit in the center of your pan. Work outward, cutting rhubarb so it will snugly fit side to side in the pan.

prepping the pan

Prepping the pan for the cake is a very important step. The LAST thing we want to happen is to bake this cake and have it stick to the pan. That would be tragic and we can’t let it happen so we are going to thoroughly grease our pan!

You can use what you want to grease the pan. I use butter but you could also use coconut oil or shortening. Take your grease of choice and thoroughly rub it all over the pan. Next we are going to add a few slices of butter in the bottom of the pan then a sprinkle of sugar. Now you can layer the rhubarb in.

making the batter

The cake batter is straightforward to make! We combine all of the wet ingredients except the greek yogurt. Combine the dry ingredients in another bowl then alternate adding the dry ingredients and the greek yogurt. You’ll have a smooth, beautiful batter that is hard to not eat!

baking the cake

Transfer the batter to your prepared pan. Depending on how big your rhubarb is you may have extra batter. If your batter is higher than your pan, take some out so it doesn’t go above the top of your pan.

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Ingredients

1 cup butter, softened + 1 tbsp for greasing the pan
1 1/4 cups white sugar + 1 tbsp for prepping the pan
2 eggs
zest of one grapefruit
1 tsp vanilla
2 cups flour
1 1/2 tsp baking powder
1/2 tsp salt
1 cup plain greek yogurt
6-8 stalks of rhubarb

Instructions

Preheat the oven to 350 F. Start by prepping the rhubarb. Wash and dry the rhubarb and line it up next to an 8 inch round cake pan (you can also use a square pan). Start with your largest piece of rhubarb and cut it to fit in the center of the pan, then move outward.
Now grease the pan. Use butter or shortening to thoroughly grease the pan, on the bottom and up the sides. Add 1 tbsp of sugar to the bottom of the pan. Shake it around until it covers the entire bottom of the pan. Press the prepared rhubarb into the pan, lining the rhubarb up snugly side by side to each edge.
Add the butter and sugar to a large bowl. Mix for 2-3 minutes until totally combined and fluffy. Add eggs, grapefruit zest, and vanilla. Mix until just combined.
In a separate bowl, combine the dry ingredients — flour, baking powder, and salt. Add half of the dry ingredients to the larger bowl. Mix until just under combined. Add half of the yogurt and mix until just combined. Repeat with the remaining dry ingredients and yogurt.
Transfer the batter to the prepared pan. Depending on how big your rhubarb is, you may have too much batter. If the batter is overflowing out of the pan, scoop it off until it is even with the height of the pan.
Bake for 45-55 minutes, until a toothpick comes out clean. Within the first 10 minutes of being out of the oven, carefully flip the pan over onto a cooling rack and slowly lift the pan up. You should be left with a beautiful upside down cake! Let it cool and enjoy.
Keep any extra cake in a sealable container.

What’d you think? I’d love to hear your thoughts or if you have any questions!