Prepare the fruit and nut mixture by combining dried cranberries, raisins, candied fruit peels, almonds, and rum. Allow the mixture to soak, stirring occasionally until you are ready to use it.
For the Dough
In the bowl of a stand mixer combine your milk, yeast, and sugar. Let the mixture rest for about 5 minutes, it should become bubbly as the yeast activates.
Add to the bowl 3 cups of your bread flour, egg, butter, vanilla, lemon zest, salt, cardamom, nutmeg, and cinnamon.
Using the dough hook attachment mix the dough on low speed to incorporate all the ingredients and bring the dough together. Once dough has come together, if it is too sticky and wet, add more bread flour ¼ cup at a time. Then allow it to mix for a few more minutes on low speed. Increase speed to medium high and mix for about 3-5 minutes, this will develop the gluten.
Remove dough from mixer and place in a lightly greased bowl and cover to proof until it has doubled in size, about 45 minutes to an hour.
While the dough is resting, create two rectangular forms with tin foil and place them on a sheet of parchment paper, these will help the stollen bread to keep it’s shape while baking. If you have stollen bread forms you can use those.
When dough has doubled in size, dump out onto a lightly floured surface and pound to degas. Fold in your fruit and nut mixture, straining out any excess juice beforehand. Work the dough until the fruit and nut mixture is evenly distributed throughout the dough. Allow the dough to rest, covered in the bowl for another 10 minutes.
Dump the dough back onto a lightly floured surface and cut it into two equal halves. Stretch each half into a rectangle and set aside. Take your almond paste and roll into a rectangle between two sheets of parchment paper. Cut the almond paste rectangle in half and place one on each rectangle of dough, slightly off to one side.
Stretch the dough over the almond paste and secure your seam on the side of the loaf, the seam will be baked on the side of the loaf to create the classic stolen bread form, just be sure to secure it tight. Place the formed loaves onto your prepared forms on the sheet pan and cover, allow the loaves to proof until just under double in size. Do a touch test to see if the loaves are ready to bake by lightly poking down each loaf about 5 times. The pokes should slightly spring back but still be visible. If they spring back and the dough is still tough they need more time, if the loaf starts to deflate when you perform the test your dough is over proofed.
Once the loaves are ready, bake them at 350° fahrenheit for 40-50 minutes. I like to rotate the pan around after about 30 minutes to ensure an even bake. You also may want to cover the loaves with foil after 30 minutes if they are browning too quickly. The loaves are ready when they are a light golden brown and temp out to 190° fahrenheit.
Remove the loaves from the oven and brush with melted butter, once the loaves have cooled a bit, dust each one generously with powdered sugar.