Soak the dried cranberries and golden raisins in rum or hot water.
Whisk the flour, cardamom, mace (or nutmeg), and cinnamon together in a large bowl, then sprinkle the salt all around the edge.
Make a well in the center, pour in ⅓ cup of the sugar, the milk, and the heavy cream, then sprinkle the yeast on top of the liquids.
Allow the yeast to dissolve, then add the eggs and vanilla.
Starting from the center and working your way outwards, stir the liquid ingredients together, gradually drawing in the dry ingredients until a sticky dough forms.
Stir in the soft butter, a tablespoon at a time, allowing each addition to fully incorporate before adding the next.
Knead the dough for a full 10 minutes.*
Cover the bowl and allow it to rest in a warm place until slightly puffed (approx. 1 hour).
Uncover, drain the dried cranberries and golden raisins well, then (on a lightly floured surface) knead them into the dough along with the candied citrus peel and almonds.
Pat or roll the dough into a circle (approx. 1-inch thick) and place it on a parchment-lined baking sheet.
Roll the marzipan into a rope (about the same length as the diameter of your circle of dough) and place it down the center.
Fold one side of the dough up and over the marzipan, then repeat on the other side, creating a slight hump shape towards the center and sealing the marzipan inside the dough.
Remove any dried fruit or almonds that may be sticking out of the surface of the dough, so they don't burn in the oven.
Mist a sheet of plastic wrap with non-stick spray, then use it to lightly cover the unbaked stollen, and allow it to rest in a warm place until slightly puffed (approx. 1 ½ hours, or overnight in the fridge).
If chilled, allow the unbaked stollen to come to room temperature.
Preheat the oven to 350 degrees F.
Gently uncover the risen loaf and bake until puffed and golden, and registering an internal temperature of approx. 190 degrees F (approx. 35 to 45 minutes).
While still warm, brush with melted butter, coat with the remaining granulated sugar, and dust generously with powdered sugar.
Cool completely before slicing.