In the small bowl, soak the raisins in the rum and 2 tablespoons hot water, covered with plastic wrap, for at least 8 hours.
Prepare the Dough
In the bowl of the stand mixer, mix the flour, sugar, salt, yeast, lemon zest, and vanilla bean at low speed.
In a small bowl, whisk together the eggs, ⅔ cup lukewarm water, and honey.
While the mixer runs at low speed, pour the egg mixture into the dry ingredients. Increase speed to medium-low and continue mixing.
Add the softened butter, 1 tablespoon at a time, mixing completely before adding each. Increase the speed to medium-high and mix until the dough is smooth and elastic, about 8 minutes.
Drain the raisins, and discard the liquid. Stir the raisins together with the candied orange peel or citron and melted butter. Stir into the dough with a wooden spoon.
Place the dough in the large bowl, cover with plastic wrap, and let rise in a cold oven with the door closed for about 12 to 15 hours, until the dough is nearly tripled in volume.
Discard the vanilla bean. Rub your hands with flour, sprinkle the top of the dough lightly with some flour, and turn out onto a floured board. Sprinkle a little more flour onto the dough.
Fold the edges into the center and place seam side down into the panettone mold. Cover with a damp tea towel (not terry cloth) and let rise in a draft-free spot at room temperature about 3 to 5 hours, until dough is just above the top of the mold.
Place the rack in the lower third (closer to the bottom than the middle) of the oven and preheat to 370° F/118° C. (If the dough is too high in the oven, the top will brown before the middle is cooked, resulting in a burned top crust.)
Place the dough in the mold on a baking sheet. Use a serrated knife to score and X across the entire surface of the dough. Place 1 tablespoon chilled butter in the center of the X.
Bake in the preheated oven about 1 to 1-¼ hours, until a wooden skewer inserted in the center comes out slightly moist but not wet or doughy. The panettone will be very dark (but should not be burned).
Pierce the skewers all the way through the panettone and through the papers. Hang the panettone upside down over a stock pot or between two objects of equal height. Cool completely, then remove the paper and slice into wedges for serving.