Melt the butter in a saucepan.
Combine the apples, sugar and cinnamon and cook for around 10 minutes till the apples are soft.
Pour into a small pan and set aside.
Preheat oven to 180 degrees.
Beat the eggs with the sugar till frothy and pale.
Add in the vanilla and beat briefly.
Sift in the dry ingredients and fold till well combined.
Pour over the apple base and spread to make it flat.
Bake for 25 minutes. Allow to cool for 5 minutes.
Serve warm as is, with a dusting or icing sugar, or with a scoop of ice cream.