Mix sauce powder and sugar. Gradually stir with 6 tablespoons of milk until smooth. Bring the remaining milk to the boil, remove from the hotplate and stir in the mixed powder with a whisk. Bring the sauce to the boil again while stirring. Leave to cool, stirring vigorously from time to time. Melt butter. For the filling, knead marzipan, raisins, ground hazelnuts and egg.
Core the apples with an apple corer, cut off the lid. Put the filling into the apples and put the lid back on. Put the baked apples in a casserole dish and sprinkle with butter. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 20-25 minutes. In the meantime, roast the hazelnut flakes in a pan without fat until golden brown. Mix sauce with cinnamon. Dust baked apples with icing sugar and serve with sauce and nut flakes