Many of us are guilty of underloving rhubarb at times because of its assertive sourness, but this rhubarb upside-down cake will change more than a few minds. It’s one of the great cakes to bake in spring, when rhubarb is in season and abundant at local farmers markets.
The tartness of the rhubarb is still present in the final cake, yet it’s balanced by the sugar and spice in the spongy, light cake below. And we still haven’t got to the biggest surprise of all—it’s pretty in pink and appealing to look at. You can comfortably complete the whole cake in less than an hour, and you can start with frozen rhubarb if you’re making this cake out of season.
Ingredients for Rhubarb Upside-Down Cake
- Rhubarb: Use fresh or frozen rhubarb, trimmed and sliced. The color doesn’t matter, but make sure the stalks have some snap in them rather than standing limp. These are the best.
- Sugar: Subbing in brown sugar will mellow the sharpness in the rhubarb.
- Flour: Use a little all-purpose flour just to give the surface of the rhubarb stalks some crunch.
- Nutmeg: The ground nutmeg will come through during baking to give the cake its aroma.
- Butter: Salted butter (melted) will help draw some of the sourness from the rhubarb and allow caramelization.
Batter:
- Butter, sugar, all-purpose flour and nutmeg: You’ll need these ingredients again to make the cake batter, along with a little salt.
- Egg: Choose a large egg at room temperature to bind the batter.
- Baking powder: This will allow the cake to rise in a relatively short time.
- Milk: The recipe calls for 2% milk to get a smooth, lump-free batter, but you can also use full-fat or your nut milk of choice.
- Whipped cream (optional): The whipped cream isn’t mandatory, but it makes a cooling, creamy topping for a warm cake.
Directions
Step 1: Make the rhubarb base
Arrange the cut rhubarb pieces in an aesthetically pleasing single layer on the bottom of a greased 10-inch cast-iron pan, heavy ovenproof skillet or springform pan lined with parchment paper. Combine the sugar, flour and nutmeg, sprinkle the mix over the rhubarb, then drizzle it all liberally with the melted butter.
Step 2: Make the cake batter
Preheat the oven to 350°F. In a large bowl, beat the butter and sugar until blended, then beat in the egg. Combine the flour, baking powder, nutmeg and salt, sifting to remove any clumps. Gradually add this dry mixture to the egg mixture, alternating with the milk and beating well after each addition, until you have a smooth, thick batter with no lumps.
Step 3: Arrange the layers and bake
Spread the cake batter over the rhubarb base and bake until a toothpick inserted in the center comes out clean, about 35 minutes. Loosen the edge immediately and invert the cake onto a serving dish. Serve warm with a spoonful of whipped cream.
Editor’s Tip: You can whisk some butter and sugar together over heat to make a caramel sauce to pour over the rhubarb base before baking.
Rhubarb Upside-Down Cake Variations
- Include sour cream: For a denser texture and fuller flavor, substitute some of the milk for sour cream or Greek yogurt. These also contain lactic acids that help the cake rise.
- Add a crunchy base: Top the cake batter with a dryish mixture of sugar, flour, spice and butter. It should have a crumbly not smooth texture. This will then become crunchy during baking, and once you invert the cake it will be the surprise at the bottom of each slice.
- Use strawberries: Sliced strawberries are a great substitute if you don’t like rhubarb, or a pleasant addition if you just want to mellow the tartness of the rhubarb.
How to Store Rhubarb Upside-Down Cake
Because it’s a moist cake with lots of sugar, you can store rhubarb upside-down cake at room temperature for a day or two, or in the refrigerator for three to four days, in an airtight container.
Can you make this rhubarb upside-down cake recipe ahead of time?
The cake mix comes together so quickly that you won’t really need to make the batter ahead of time, but you can certainly freeze whatever fresh rhubarb stalks you have in advance. You don’t even need to thaw them before baking. They’re oven-ready while frozen.
Rhubarb Upside-Down Cake Tips
Why isn’t my rhubarb upside-down cake light and fluffy?
Part of the pleasure of this recipe is breaking through the caramelized rhubarb to a soft, light cake underneath. But if you overmix your batter, you’ll get a dense, heavy texture. Make sure your egg is at room temperature before mixing or your batter will split and you’ll have to start again.
How do I stop my cake from sticking to the pan?
The flip is the highlight of this recipe, but a stuck cake can ruin the effect. Your pan needs to be properly greased all over, and you should release the cake from the pan while it’s still warm. If it cools, the sugars will stick.
What can I serve with rhubarb upside-down cake?
Don’t expect a strong rhubarb taste (or texture) once the cake emerges from the oven, but there will be a little lingering acidity. Serve the warm cake with ice cream and you’ve got a perfect pairing.
