Chop up the spiced speculoos, mix with the butter and press firmly into a greased springform pan.
Peel the apples, cut into eighths and cut into small pieces. Mix the pudding powder with a little apple juice. Bring the apple pieces to the boil together with the remaining apple juice, sugar and vanilla sugar, reduce a little, then remove from the stove and stir in the mixed pudding powder, bring to the boil once. Pour the mixture on the speculoos cake base and let it set overnight in the refrigerator.
Mix the sour cream, cream and vanilla sugar and spread over the apple mixture. Garnish with speculoos crumbs if you like.