Martha’s Rhubarb Upside Down Cake is a sweet, tart and a delightfully spongy cake. What starts out as a streusel topping becomes the crumbly bottom with a stunning mosaic rhubarb top! Serve with whipped cream or vanilla ice cream and a cup of hot coffee.

close up of Martha's Rhubarb Upside Down Cake

One day I’d love to meet Martha Stewart. Maybe she will have me on her show? Does she still have a show? And if not what happened? But if she still does where can I find it??

First thing I would tell her would be how much I love this cake.

She definitely knew what she was doing when she came up with the recipe for this Rhubarb Upside Down Cake. It’s my favorite recipe to use the rhubarb from my garden. There’s a lot of butter and sugar going on in this cake, but I personally believe that all things in moderation. Plus there’s rhubarb in it so it’s basically healthy right? (lie to me)

I only made a few tweaks on her recipe, like reducing the flour and adding a little vanilla and more orange zest into the cake batter. Nothing major but does make all the difference.

The rhubarb in this cake is tart and delicious which is a great contrast to the sour cream cake that is soft, spongy and with a subtle tang. The crumble topping adds a delicious texture. The dessert as a whole is a winner.

ingredients on white background

To Make Martha’s Rhubarb Upside Down Cake You Will Need:

for the crumble topping:

  • unbleached all-purpose flourThe base of the crumb mixture.
  • granulated sugarFor sweetness and crunch.
  • kosher saltThis balances the sweetness.
  • unsalted butterThis is what binds the crumble mixture together.

for the rhubarb:

  • fresh rhubarbSour and tangy once baked.
  • granulated sugarThis is needed to balance the tang of the rhubarb and draw out the liquids.

for the cake:

  • unbleached all-purpose flourProvides the structure for this cake recipe.
  • baking powderReacts with the heat to give a leavening boost while the cake is in the oven.
  • kosher saltFor flavor and balancing sweetness.
  • unsalted butterAdds flavor, moisture, gives this cake a soft texture and aids in leavening.
  • granulated sugarBesides sweetness, it also adds flavor, bulk, and structure.
  • orange zestAdds bright citrusy notes.
  • fresh orange juiceFor moisture and flavor.
  • real vanilla extractEnhances all the other flavors in the recipe.
  • eggsProvide structure, leavening and add richness, color, and flavor.
  • sour creamWill make the cake moist and rich.

pouring butter into bowl with flour and sugar.

Make the Crumb Topping:

In a medium mixing bowl, measure and add 1/2 cup flour, 1/4 cup sugar, 1/8 teaspoon of kosher salt and pour in 1/4 cup (4 tablespoons) melted butter.

crumb topping in clear bowl.
Stir together until large clumps form, and set aside.

PREPARE The Rhubarb:

rhubarb on white background

Take 1 pound of fresh rhubarb and give it a good scrub and pat dry, then trim off the rough or dried ends and discard.

Holding your knife at a sharp angle, make slices about a half an inch thick working your way down the stalk. It doesn’t have to be precise, but definitely keep those little end bits too because they’re good for filling in the small empty spaces.

sliced rhubarb and sugar in bowl.

Throw the sliced rhubarb in a large mixing bowl with 3/4 cup sugar.

sliced rhubarb tossed with sugar in clear bowl.

Stir and let them sit. The sugar will pull the juice out of the rhubarb.

Greased cake pan dotted with 1/2 stick of butter.

Generously grease a 9-inch pie pan with nonstick spray. Dice a 1/2 stick of butter in to pieces and then drop it into the pan.

sliced rhubarb mosaic-ly pressed into pan.

Lay the sliced rhubarb on its side making a mosaic like pattern, using the dots of butter to hold them in place. I think Martha just dumps her rhubarb in, and you could do that too if you wish, however I think this looks way prettier!

Keep going and use the smaller pieces to fill in the gaps. Spoon a little (not all) of the rhubarb sugar over top or don’t. This step is optional.

For The Cake Batter:

Cake dry ingredients whisked in glass bowl.

In a large mixing bowl, whisk together 1 cups flour, 1-1/2 both teaspoons baking powder and kosher salt until combined.

1 stick of butter.

Add 1 softened stick (8 tablespoons) of butter (I know more butter) and 1 cup sugar into a large mixing bowl.

butter and sugar creamed together in stand mixer.

Cream the butter and sugar on medium speed until light in color and fluffy.

orange zest on microplane.

Meanwhile quickly grate 1 teaspoon orange zest and add it to the butter/sugar mixture.

pouring 1 tablespoon fresh orange juice into cake batter.

Juice 1 tablespoon of fresh orange juice and add that in as well.

adding 1 teaspoon vanilla extract.

Add in a teaspoon of vanilla extract and mix on low speed until combined.

adding one egg at a time.

Next add in 2 eggs, one at a time until mixed thoroughly, scraping down the sides in between.

add dry ingredients to batter.

Then alternately add a spoonful of the dry ingredients…

alternate dry ingredients with sour cream.

Alternate adding a spoonful at a time of the (1 cup) sour cream, until all ingredients are incorporated.

cake batter in stand mixer bowl.

This cake batter smells like citrus, vanilla with a sour cream tang. So. Good.

cake batter poured over rhubarb.

Pour the batter over top of the rhubarb and spread evenly with an offset spatula.

upside down cake sprinkled with crumb topping.

Sprinkle the crumb topping over top, breaking any extremely large clumps into smaller ones.

This crumb topping will eventually become the bottom. swoon.

Place on a rimmed metal baking sheet and slide onto the middle rack in your preheated 350° oven and bake for 45 to 55 minutes. Or until a toothpick inserted into the center comes out clean and the cake top sort of springs back when touched. In my teeny hotbox of an oven it is closer to 45 minutes.

freshly baked rhubarb upside down cake.

The rhubarb will bubble and may spill over, luckily the sheet pan will catch it and not dirty the bottom of your stove. Remove and let cool for ten minutes.

running a knife around cake edge to loosen.

Once it has cooled for the ten minutes; run a knife around the edge of the cake to loosen.

carefully invert Martha's Rhubarb Upside Down Cake onto stand and remove pan.

Invert on to your favorite platter or cake stand and let cool completely.

side view of Martha's Rhubarb Upside Down Cake.

I wasn’t getting the pictures I wanted indoors, the lighting in my kitchen was weird that day and it wasn’t doing this cake any justice what-so-ever.

Slice of Martha's Rhubarb Upside Down Cake.

So I sliced me a sliver and took it outside and then… the color popped!

slice of Martha's Rhubarb Upside Down Cake with a scoop of vanilla ice cream on top.

This cake is deliciously dessert-y and yet the leftovers are perfect for a late breakfast or brunch alongside a steaming cup of tea or coffee. The crumble bottom adds a surprising texture to this delicious spongy cake. And of course the rhubarb is everything.

It literally is heaven on a plate.

The end.

Enjoy! And if you give this Martha’s Rhubarb Upside Down Cake recipe a try, let me know! Snap a photo and tag me on twitter or instagram!

Martha's Rhubarb Upside Down Cake on white pedestal cake plate.

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Yield: 12 servings

Martha's Rhubarb Upside-Down Cake

Martha's Rhubarb Upside Down Cake is a sweet, tart and a delightfully spongy cake. What starts out as a streusel topping becomes the crumbly bottom with a stunning mosaic rhubarb top! Serve with whipped cream or vanilla ice cream and a cup of hot coffee.

Ingredients

FOR THE CRUMBLE TOPPING:

  • 4 tablespoons unsalted butter, melted
  • 1/2 cup unbleached all-purpose flour
  • 1/4 cup sugar
  • 1/8 teaspoon kosher salt

FOR THE RHUBARB:

  • 1 pound rhubarb, trimmed and cut on a very sharp diagonal about 1/2 inch thick
  • 3/4 cup sugar

FOR THE CAKE:

  • 3/4 cup unsalted butter, divided, at room temperature, plus more for buttering pan
  • 1 cup granulated sugar
  • 1 cup unbleached all-purpose flour
  • teaspoons baking powder
  • teaspoons kosher salt
  • 1 teaspoon orange zest
  • 1 tablespoon orange juice, finely grated
  • 1 teaspoon real vanilla extract, freshly squeezed
  • 2 large eggs
  • 1 cup sour cream

Instructions 

Make the Crumble Topping:

  • Start by stirring together melted butter, flour, sugar, and salt until moist and crumbly, then set aside.

MAKE THE RHUBARB:

  • Toss prepared rhubarb with sugar; let stand tossing occasionally.

Make the Cake:

  • Spray (or butter) a 9-inch round cake pan (that is at least 2-inches deep) with nonstick spray then dot with a half stick of butter that has been cut into pieces.
  • Toss the rhubarb again, and place rhubarb on its side in a mosaic like pattern, using the butter to hold it up. Use the small pieces of rhubarb to fill in the gaps. Spoon a little (not all) of the rhubarb sugar over top. However this step is optional.
  • Preheat oven to 350 °.
  • Whisk together the flour, baking powder, and kosher salt.
  • In the bowl of your stand mixer, beat remaining stick of butter and sugar in your mixer on medium speed until light in color and fluffy.
  • Add in the orange zest, orange juice and the vanilla extract .
  • Crack in the eggs, one at a time, until incorporated, scraping down sides of bowl in between.
  • Alternate adding in the 1/3 of the flour mixture with 1/3 of the sour cream and repeat, mixing until smooth.
  • Spread the cake batter over the rhubarb, then sprinkle with the crumble topping evenly over batter.
  • Place the cake on a foil-lined sheet pan (to catch any spill over) and bake for 45 to 55 minutes or until a toothpick inserted into the center comes out clean and top springs back when touched.
  • Allow the cake to cool 10 minutes before running a knife around edge of the cake, and inverting it onto your favorite platter or cake stand.
  • Let cool completely before serving with whipped cream or vanilla ice cream.

Notes

Nutrition Disclaimer: All information presented on this site is intended for informational purposes only. I am not a certified nutritionist and any nutritional information shared on SimplyScratch.com should only be used as a general guideline.
Serving: 1slice, Calories: 380kcal, Carbohydrates: 48g, Protein: 4g, Fat: 20g, Saturated Fat: 12g, Polyunsaturated Fat: 1g, Monounsaturated Fat: 5g, Trans Fat: 1g, Cholesterol: 82mg, Sodium: 399mg, Potassium: 173mg, Fiber: 1g, Sugar: 34g, Vitamin A: 678IU, Vitamin C: 4mg, Calcium: 95mg, Iron: 1mg