Make the soaker and let it sit, covered on the counter for 12-24 hours.
After the soaking time has elapsed, make the pre-dough a big bowl by whisking together the pre-dough ingredients and letting them sit, covered for at least one hour.
Add the main dough ingredients to the pre dough and knead well for 10 minutes by hand or by machine on the lowest setting, and let rest for 30 minutes, covered
Pull the dough out of the bowl and add in the soaked fruit and nut mix by squishing, folding, kneading, pleading, begging, picking it off the floor, and "chopping" it in gently with a dough scraper. You have been warned. Make sure your floor is clean. Do not do this in the mixer as you will squish the raisins into brown smears.
Let it rest for two hours, covered. It will not exactly rise, there is too much fruit for that, but it will become a bit puffier.
Pull the dough out onto a counter that is not floured and, using a knife or scraper, divide it into four equal pieces.
Gently stretch/pat each piece into a rectangle about the size of a piece of A4/81/2 x 11" paper. It should be about about 2.5 cm/1 inch thick. At this point, if you are adding marzipan, shape it into thin sausage, no more than 1 inch/2.5 cm in diameter and lay it down the middle of each square. Fold the right-hand edge of the dough square 2/3 of the way over the dough (and over the marzipan if you have added it) and then fold the left-hand edge all the way over the dough to the right-hand edge. Like folding a piece of A4 paper (81/2 by 11") for an envelope.
Cut four rectangles of non stick parchment that are twice as wide and ten centimeters (3-4 inches) longer than each piece of shaped stollen. This parchment will be what you use to move the stollen around. It is too fragile, when it comes out of the oven, to pick up without this support.
Place each stollen on a separate rectangle and then place them all on a baking tray, with plenty of space between them.
Cover the loaves with a tea towel and let the loaves rest while you heat the oven to 250 centigrade. Put the stollen in and immediately reduce the heat to 180 C.
Bake for 50 minutes. After 30 minutes cover them with huge sheet of baking parchment to prevent the raisins from burning.
Remove them from oven and immediately place each loaf carefully on a cooling rack. Brush them with half of the melted butter. Sprinkle each one with one tablespoon of vanilla sugar. Use a tiny sieve to sift 1 tablespoon of icing sugar over each one then dribble on 125 g more butter. I really do mean dribble. You cannot brush on this last coating of butter or you will brush away the sugar. So, dribble with a spoon. Then, sift the remaining icing sugar over the tops of all of them.
Let these cool completely (this takes a few hours).
Tear four huge pieces of wax/greaseproof/parchment. Place one stollen (using the parchment it is sitting on to move it) in the middle of each piece and wrap them up well. Then, wrap them tightly in aluminium foil. Store in a cool dry place for 4-6 weeks before eating.