Remove the cores from the apples with a cookie cutter. Brush the inside with lemon juice. Lightly grease an ovenproof dish with butter. Put the apples in.
Mix the honey, almond slivers and sultanas, pour into the apples, cover with the apricot jam and the remaining butter in flakes. Fry in the preheated oven at 200 ° C / gas: level 3 for about 25 minutes.
For the sauce, bring the milk and cream to the boil and remove from the heat. Mix the egg yolks with cornstarch, sugar and vanilla sugar in a saucepan. Beat on very low heat until frothy. Slowly add the milk and cream mixture, stirring vigorously until the sauce is thickened. In no case let it boil!
Arrange the apples, pour a little sauce over them. Serve the rest of the sauce separately.