1. Preheat the oven to 180 degrees Celsius.

2. Peel and core the apples, slice them into thin slices.

3. In a bowl, mix together the rice flour, brown sugar, and a pinch of salt.

4. In a separate bowl, mash the bananas and add the eggs. Mix well.

5. Add the wet ingredients to the dry ingredients and mix until well combined.

6. Gently fold in the apple slices.

7. Grease a baking pan with butter and evenly spread the batter in it.

8. Bake the cake for about 40-45 minutes, until golden brown and a toothpick comes out clean.

9. Remove from the oven and let it cool before serving.