Apple Upside-Down Cake (Gluten Free)

Gluten Free Apple Upside Down Cake is moist, light and fluffy, with perfectly caramelised apples baked into the top.

Caramelised Apple Top:
½ cup unsalted butter (115 g)
1 cup light brown sugar, packed (200 g)
¾ tsp. ground cinnamon
1 pinch sea salt
3 apples, thinly sliced

Upside-Down Cake:
2⅔ cups all-purpose gluten-free flour blend (330 g)
2 tsp. baking powder
½ tsp. baking soda
1 tsp. ground cinnamon
½ tsp. sea salt
2 cups white sugar (400 g)
1 cup unsalted butter, at room temperature (230 g)
4 large eggs, at room temperature
1 tsp. pure vanilla extract
⅓ cup buttermilk, at room temperature (80 mL)

Preheat your oven to 325°F (165°C/140°C fan, Gas Mark 3). Line a 9x13" deep cake tin (or brownie tin) with parchment paper.

Make the Caramelised Apple Top:
Melt the butter in a small saucepan over a medium heat, add brown sugar and stir to combine. Bring to a boil.

Remove from heat and stir in the cinnamon and salt.

Pour the mixture into your lined pan and spread out. Arrange apples over the top. Set aside.

Make the Cake:
Put the flour, xanthan gum (if using), baking powder, baking soda, cinnamon and salt in a bowl and whisk together to combine. Set aside.

In your stand mixer with the paddle attachment, or using a handheld electric beater, beat the butter and sugar together on a high speed until light and fluffy, about 2-3 minutes.

Add the eggs one at a time, beating in between each addition. Beat in the vanilla extract.

Add ⅓ of the flour mixture and beat on a low speed to combine. Add ½ of the buttermilk and beat to combine. Repeat this step with the remaining flour mix and buttermilk, with the last addition being the final ⅓ of the flour mix.

Pour the batter over the apples and spread out carefully.

Bake for 60-75 minutes, until the cake is springy to touch and skewer comes out clean (don't push the skewer all the way to the bottom, or it will always come out with a wet caramel on it.).

Cool in the tin, then turn out so the bottom is now on the top. Slice into squares and serve.

Makes 15 slices.

Cook's Notes:

• I use Bob's Red Mill 1-for-1 GF flour blend. If gluten isn't a concern for you, you can use regular all purpose/plain flour in the same measurements.
• I make my buttermilk at home, for this recipe add ½ Tbsp. fresh lemon juice or white wine vinegar to your measuring jug, then fill up with milk to the ⅓ cup/80 mL. Let sit for 5 minutes. It will look a little curdled.
• You can use your favourite type of apple, but the tarter types tend to work better to balance the sweetness of the caramel and cake.