Gluten-Free Apple Upside-Down Cake

What is an upside-down cake?

An upside-down cake is baked upside-down in the pan and then turned out while warm to reveal a beautiful topping. The presentation is half the fun, but the taste and texture are also what makes an upside-down cake stellar. A layer of fruit and sugar is arranged on the bottom with cake batter spread over top. While the cake bakes, the sugars and fruit caramelize on the bottom. While warm, the cake is flipped right-side-up to unveil the fruit sitting right on top, while the juices and caramelized sugars ever-so-slowly seep into the perfectly-baked cake below. 

Unlike a cake baked with the fruit on top of the batter, an upside-down cake does not run the risk of the fruit sinking into the cake or the juicy fruit causing an underbaked or too moist cake.

Flours for Gluten-Free Apple Upside-Down Cake

When making gluten-free cake, I prefer using a homemade blend of flours to enhance the flavors of the cake I'm making. This gluten-free apple upside-down cake uses a blend of oat flour, sweet rice flour, tapioca flour, and teff flour.

If you're apprehensive about buying four different flours, I understand. Here are four fall-forward recipes you can make using oat, teff, and sweet rice flour and about a billion more that use oat, tapioca, and sweet rice flour. With these four flours, you can make countless cakes and cookies this season! Additionally, each of these flours freeze well for up to 6 months. Or, find my recommendations below for substitutions if you can't find or don't have that particular flour. 

Alternatively, if you'd prefer to use a pre-made blend, you can sub out all the flours by weight (239g) along with the xanthan gum with Bob's Red Mill 1-to-1 all-purpose gluten-free flour blend.

Bob’s Red Mill gluten-free oat flour: Oat flour adds lightness and structure to the fluffy crumb. It keeps the cake super moist, but not overly dense. If you don't have oat flour, you can make your own by grinding gluten-free rolled oats in a blender or food processor until fine, then sifting out any larger pieces. 

• Substitution: Sub in by weight with gluten-free sorghum flour or Bob's Red Mill 1-to-1 all-purpose gluten-free flour blend. I've made the cake with sorghum flour rather than oat flour and it's equally as delicious!

Sweet rice flour: Sweet rice flour is necessary for the chewy texture of this cake. Also called "Mochiko, sweet rice flour is distinctly different from white rice or brown rice flour. Rather it is the same flour used to make mochi, and as such, its stickiness helps to bind the cake together, creating chewiness like a classic cake recipe. It’s gluten-free baking’s secret weapon. 

• Substitution: I do not recommend substituting the sweet rice flour in this recipe. While I haven't tested it, you could *try* subbing the sweet rice flour for additional tapioca flour, but your results will vary and I can't promise it will turn out as delicious.

Bob’s Red Mill tapioca flour: Tapioca flour adds chewiness and helps mimic the fluffiness of a classic cake. It adds just a bit more softness and loftiness to the crumb. 

• Substitution: Sub in by weight arrowroot starch, potato starch, Bob's Red Mill 1-to-1 all-purpose gluten-free flour blend, or using equal parts more oat flour and sweet rice flour, by weight. 

Bob’s Red Mill teff flour: Teff flour is such a warm flavorful flour that's the perfect pairing for a spiced cake. In this cake, teff flour is the flavor driver. You don't need a lot to get the flavor benefits. As a powdery fine flour, it bakes up soft and fluffy with rich toffee notes that accentuate the caramelized apple topping. 

• Sub in by weight: You can sub in 15g more each of sorghum flour, sweet rice flour, and tapioca flour, but your cake will turn out lighter in color and less flavorful. You could also sub in chestnut flour, millet flour, or Bob's Red Mill all-purpose gluten-free flour.

Xanthan gum: Without xanthan gum, the batter is thin and seeps up under the apples and the cake bakes up dense.

Ingredients for gluten-free apple upside-down cake

• Bob’s Red Mill gluten-free oat flour
• Sweet rice flour: Bob's Red Mill or Koda Farms Mochiko
• Bob’s Red Mill tapioca flour
• Bob’s Red Mill teff flour
• Xanthan gum
• Spices & leaveners: ground cinnamon, ground nutmeg, baking powder, baking soda, kosher salt
• Unsalted butter, room temperature
• Granulated sugar
• Large eggs
• Vanilla extract
• Whole milk
• Sour cream: you can substitute whole milk greek yogurt

What kind of apples for baking

The best apples for cakes are crisp apples that hold up against the heat of baking. My top choices are Granny Smith and Honeycrisp. 

Granny Smith apples have a natural tartness that balances dessert nicely, while Honeycrisp apples are crisp and firm with a nice combination of sweet and tart. 

How to make a gluten-free caramel apple upside-down cake

Without the need to make frosting, gluten-free upside-down cakes are super easy to make! Here are the steps:

1. Melt the butter and sugar: Add vanilla and salt, then spread it into a parchment-lined cake pan. 
2. Arrange thinly sliced apples on top.
3. Sift dry ingredients.
4. Cream butter and sugar, then add egg and vanilla.
5. Slowly add dry ingredients in three parts, alternating with milk and sour cream.
6. Pour over apples and bake. 
7. Cool & flip: Let cool 5-10 minutes, then flip out of the pan onto a wire rack to cool completely.

Tips for apple upside-down cake

Use a cake pan with high sides

For this cake, you need a cake pan with at least 2-inch high sides. With a layer of apples underneath, this cake is quite tall. As the cake batter has its initial rise, it will fill the entire 2-inch pan. As the apples cook down, they will create space so it won't overflow.

Line the bottom with parchment paper

To ensure your sticky caramelized apples don't stick to the pan and get left behind when you turn out the cake, line your cake pan with a round of parchment paper. Once flipped, you can carefully peel off the parchment paper to reveal the warm tender apples.

Flip shortly after baking

If you wait too long to flip the cake, the caramelized sugars and fruit will begin to set up and harden, causing them to stick to the pan. Instead, let the cake cool only 5-10 minutes before flipping. 

Serve warm or at room temperature

This cake is delicious served warm or after it has cooled completely. To serve warm, let it cool 30 minutes before slicing so the crumb sets up. Alternatively, you can heat fully cooled slices for 10 seconds in the microwave and serve with a scoop of vanilla ice cream. 

How to flip an upside-down cake

While upside-down cakes are simple to bake, paying close attention to the timing of flipping the cake is crucial. Cool the cake just 5-10 minutes after it comes out of the oven before flipping. Cooling any longer than 10 minutes will result in the caramelized sugars and fruit firming up and the fruit will stick to the bottom. 

To flip, start by running a thin knife around the outside of the cake. Place a wire rack over the top of the cake pan and have a plate or baking sheet nearby to catch drips. Using oven mitts to hold the cake pan and the wire rack tightly together, flip the cake over and set the wire rack onto the plate/baking sheet. Carefully and slowly lift the cake pan to release the cake. Peel off the parchment paper.

Spoon any remaining caramel from the pan over the top, and if any apple pieces are stuck to the pan, carefully arrange them back on the cake. Let cool for at least 30 minutes before slicing and serving.

How to store upside-down apple cake

Store leftover apple upside-down cake covered at room temperature for 24 hours or in an airtight container in the fridge for up to 3 days. If chilled, cool to room temperature or microwave for 15-20 seconds before serving. 

To freeze, let the cake cool completely first, then store the whole cake or individual slices wrapped tightly in the freezer for up to 3 months. Defrost to room temperature before serving. 

More Gluten-Free Fall Cakes

• Gluten-Free Banana Upside-Down Cake
• Gluten-Free Pumpkin Roll
• Gluten-Free Carrot Cake
• Gluten-Free Gingerbread Cake with Eggnog Frosting
• Cardamom Cranberry Gluten-Free Coffee Cake
• Gluten-Free German Apple Cake