Add egg, sugar, milk, and buttermilk to a bowl and whisk thoroughly.
Add the levain to the mix, and break up and whisk until levain dissolves into liquid.
Once levain is mixed in, add flour and salt and stir well until a stiff dough is made. Cover with a wet towel and set aside for an hour.
Scoop dough onto a cutting board and add some little pats of butter to the dough. Fold over, knead slightly, and repeat adding of butter, folding and kneading until butter is incorporated into the dough. Cover and let set for 15 minutes.
Flatten out dough with hands, into a rough rectangle and take the fruit (strain any excess juice) and press it into dough. The dough will get a bit slippery but keep pressing into the dough, working it in as best as you can. Knead it until fruit is well incorporated into dough.
Place back into bowl, and cover. Place in a warm spot to rise 50% or cover with plastic and refrigerate overnight if you want to slow ferment your stollen further.
When dough is ready (let warm for about an hour if you refrigerated overnight), divide into two on a cutting board and flatten each dough into rough rectangles with hands.
Get your marzipan and divide into two. Roll into 2 long pieces and place one each onto the right edge of the dough.
Sprinkle your cinnamon and nutmeg spices over each of the doughs.
Grab the edge of the dough and carefully fold over the marzipan, rolling it until you have a rolled up loaf. Do the same for the other dough. Transfer onto cooking sheet keeping the seam sides down.
Cover with plastic wrap or wet tea towel and let proof in a warm spot until 50% risen again.
When ready to bake, preheat oven at 350°F and place in oven for approximately 35-40 minutes, until loaves are a nice golden colour.
Remove from oven when stollen is done and allow to cool for a bit.
Melt butter in pot/pan and brush each loaf thoroughly with melted butter.
Allow to cool for an hour or so, then get a sifter and powder loaves with powdered sugar on all sides.
You could slice it up at this point, or cover and let loaves set for another day.