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This Rhubarb Cake is gluten-free, grain-free, made with Almond Flour. Deliciously addictive, perfect for Spring! Make it upside-down or right-side up, your choice!

Rhubarb Cake


This upside-down Rhubarb Cake is baked in a cast iron skillet. It’s gluten-free- and grain free- made with Almond Flour. Deliciously addictive and perfect for Spring.


Units Scale

Rhubarb Topping

  • 4 cups rhubarb, cut into 1/2 inch cubes (try to use red parts for the prettiest presentation)
  • 3/4 cup sugar
  • 3 tablespoons butter
  • 1 teaspoon fresh lemon juice
  • 1 teaspoon vanilla
  • pinch salt

Almond Flour Cake


  1. Preheat oven to 350 F
  2. Over medium heat, melt butter into a well-seasoned, 9-10 inch cast iron skillet, and brush the sides with it. Add rhubarb, 1/2 cup sugar, lemon juice,  vanilla and pinch salt and simmer for 2-3 minutes, just until combined and sugar has dissolved. Turn the heat off. Do not cook rhubarb all the way through.
  3. In a medium bowl, whisk the eggs with olive oil and honey. Add the lemon juice, lemon zest, vanilla, and cardamon, and salt.
  4. Whisk in the baking powder and the almond flour a little at a time. You will have a very sticky batter at this point.
  5. Make sure the edges of the skillet are greased with butter. Pour batter over rhubarb in the cast iron skillet and place in a preheated oven, middle rack for 30-45 minutes.
  6. While baking, make sure to have ready what you plan to flip the cake onto. At 30 minutes, check for doneness by inserting a toothpick or skewer into the middle of the cake. If it comes out clean, it is done. If not, continue baking longer, and check again every 5-7 minutes. Pull from the oven, let sit 5 minutes, run a sharp knife around the edges, then place a cake platter or cake stand over the skillet, and invert, gently tapping the bottom of the skillet so it releases.
  7. Serve with vanilla ice cream or whipped cream.


I use a 10-inch cast iron skillet for this recipe! I’ve tried it with a 9-inch spring form pan- and no leaks- but some readers have had issues with leaks. So if using a spring form pan, line the bottom with parchment and bake over a sheet pan.

Feel free to add almond extract, more almond flavor.


  • Serving Size:
  • Calories: 346
  • Sugar: 32.9 g
  • Sodium: 331 mg
  • Fat: 12 g
  • Saturated Fat: 4.4 g
  • Carbohydrates: 39 g
  • Fiber: 2 g
  • Protein: 6.8 g
  • Cholesterol: 108.3 mg

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