Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.

In a large mixing bowl, whisk together 2 cups of gluten-free all-purpose flour, 1 teaspoon of baking powder, ½ teaspoon of baking soda, ½ teaspoon of salt, and 2 teaspoons of cinnamon.

In another bowl, combine ½ cup of melted unsalted butter, ½ cup of granulated sugar, ½ cup of packed brown sugar, 2 large eggs, and 1 teaspoon of vanilla extract, whisk until smooth.

Gradually add the dry ingredients to the wet ingredients and stir until just combined. Fold in 2 cups of peeled and diced apples.

Pour the batter into the prepared cake pan and bake for 30-35 minutes until a toothpick comes out clean.

While the cake cools, whisk together 1 cup of powdered sugar and 2-3 tablespoons of milk until smooth to make the glaze.

Drizzle the glaze over the cooled cake and allow it to set before serving.