Before eating it's best stored at least a few days once buttered and sugared so the crumb becomes slightly firmer.
Combine the white flour, sugar, salt, spices, yeast and fruit in a large mixing bowl. Whisk and boil the milk and rye flour. Spoon the paste into another bowl, Return the pan to the hob, melt the butter then beat this into the milk mixture with the eggs, rum and zest. Stir this into the flour and mix well. Leave for 10 minutes then lightly knead it, return to the bowl and leave for 1 1/2 hrs. Knead the dough once more then roll out into an oval measuring 25cm x 20cm. Lay the marzipan in the middle, fold the dough over and press through the dough around the bump of the marzipan to seal it. Lay the dough on a tray, cover with a cloth, leave until doubled then bake at 180C (160C fan) for 35 minutes. When cold cover completely with a thin layer melted butter, then a thick layer of icing sugar, and wrap snugly in wax paper to store.