Soak the dried fruit in 100ml of hot water. Gently warm the apple juice for a few mins in a pan, then add the yeast and leave to activate for 10-15 mins (it will start to bubble).
Put the flour in a bowl. Stir in the yeast and apple juice mixture to form a smooth dough, then cover and leave to prove somewhere warm until roughly doubled in size, about 1-2 hrs. You can also put the dough in the fridge to rise slowly overnight.
Drain the fruit and add to the dough along with the nuts, spices and marzipan. Squish everything together, then turn the dough out onto a lightly floured work surface and knead until the fruit stays in the dough.
Shape the dough into a sausage shape and put it on a baking tray lined with baking parchment. Cover with a clean tea towel and leave to prove somewhere warm for 30 mins–1 hr until it has risen by about a quarter.
Heat oven to 180C/160C fan/gas 4. Bake the stollen for 20 mins, then reduce oven to 150C/130C fan/gas 2 and bake for 25-30 mins more until golden brown and firm to the touch.
Remove the stollen from the oven and brush all over with the melted butter. Dust with the icing sugar and leave to cool completely before slicing. Store any remaining stollen, well wrapped, in an airtight container.