Preheat oven to 180°C and line a cake tin with parchment paper.
Peel the apples and cut into small cubes.
Add 1 tablespoon sugar to the apples and mix.
Mash the bananas and mix with the eggs, oil and vanilla-extract.
Add sugar and mix well.
Now add the flour, baking powder and cinnamon and mix until no lumps remain.
Fold in the apples and oats.
Pour the batter in the prepared cake tin and bake ca. 50-60 minutes in the middle of the oven.