Process butter, sugar, egg, baking powder and flour into a dough and place in a greased springform pan.
Then peel the apples and remove the core with an apple cutter. Halve the apples, retain one half and place the halves on top of the batter. Pour the raisins into the holes of the apples, cut one half of the apple into small pieces and fill the pieces into the spaces between them.
For the cream, remove 5 tablespoons from the milk and mix well with the eggs, custard powder and flour in a bowl. Bring the rest of the milk with the cream and sugar to a boil in a saucepan. Slowly add the hot liquid to the egg mixture while stirring. Spread the icing over the apples. Then generously sprinkle sugar and cinnamon over the mixture.
Bake at 180 ° C top / bottom heat in a preheated oven for 1 hour.