DAY BEFORE BAKING: In a bowl, add raisins, candied fruit, almonds and rum. Cover place in refrigerator and let sit overnight.
Warm milk, then add yeast packet and a pinch of sugar. In about 10 minutes, it will bubble.
Mix flour, egg, yeast mixture, sugar, vanilla extract, lemon zest and salt in a stand mixer using the dough hook for several minutes. Dough should just come together and not be very smooth yet. Remove from bowl and set aside.
Cream butter and 2/3 cup flour with the nutmeg and cardamom. Add dough back to the bowl and work the dough with a dough hook until the butter and flour mixture is smooth. Cover and let dough rest for 30 minutes.
Turn dough out onto lightly floured surface. Knead in fruit/almond mixture. Let rest 15 minutes.
Form dough into a rectangle, then fold the left side over the middle, then the right side over the top, to create a "loaf"shape.
Place dough inside in a long bread or stollen pan. Let dough rise for 30 minutes in a warm location.
Preheat oven to 350 degrees. Brush melted butter across top of loaf. Bake for 35-45 minutes or until golden brown. Remove from oven, brushing again with butter, then dusting with a heavy coating of powdered sugar. Let cool completely.
Stollen only gets better over time when stored properly. Wrapped tightly in plastic, you can enjoy it throughout the holiday season.