Sift the flour into a bowl and make a crater in the center. Into the crater, add 1/4 c. of the confectioners' sugar and 1/4 cup of the milk. Sprinkle the yeast over the milk and dust the yeast with a little flour. Let the yeast develop for 15-20 minutes.
Add the butter, lard, egg, salt, remaining sugar, vanilla extract, rum, cinnamon, grated lemon peel, slivered almonds, candied lemon and orange peels, and raisins. Add only enough of the remaining milk to make dough pliable. Knead thoroughly and cover the dough with a damp towel and let it rise overnight.
Knead again for 1 minute then shape the dough into a loaf and put it on a large buttered baking sheet. Use your fingertips to push back into the dough any raisins that may have popped up to prevent scorching. Baste the loaf with tablespoons of milk and bake in a preheated oven at 350 degrees for approximately 50 minutes. Stollen must turn golden brown. Test to make sure it is done with a toothpick.
Baste the stollen generously wih butter while it is still hot, then sprinkle with powered sugar. Repeat this process in order to attain a nice white surface and to help keep the stollen fresh and moist for several weeks. It's best to store for at least a week before serving.