Peel the apples and remove the core. Cut into wedges and place in a baking dish. Now sprinkle the apples with the cinnamon and sugar and pour in the water. Crumble the rusks and spread them over the apples. Now divide the butter or margarine into flakes and place on the crumb layer.
Bake in a preheated oven at 200 ° C for about 30 minutes.