Ingredients
Method
Soak raisins in rum and 2 Tbsp. hot water at room temperature, stirring occasionally, until raisins are plump and most of liquid has been absorbed, 8 hours or overnight.
Mix flour, sugar, salt, yeast, zest, and vanilla bean in mixer at low speed until combined. Whisk together eggs, tepid water (⅔ cup), and honey in a bowl. With mixer at low speed, pour egg mixture into flour mixture. Increase speed to medium-low and mix to combine. Add 10 ½ Tbsp. softened butter, 1 Tbsp. at a time, mixing until incorporated before adding more. Increase speed to medium-high and mix until dough is smooth and elastic, about 8 minutes.
Drain raisins, discarding soaking liquid, then stir together with citron and 1 Tbsp. melted butter. Stir into dough with a wooden spoon.
Place dough in a large bowl, cover with plastic wrap, and let rise in cold oven with door closed until nearly tripled in volume, 12 to 15 hours.
Discard vanilla bean, then sprinkle dough lightly with flour and scrape out onto a lightly floured surface. Sprinkle a bit more flour onto dough. Fold edges into center and place, seam side down, in panettone mold. Cover with a damp kitchen towel (not terry cloth) and let rise in a draft-free place at warm room temperature until dough is just above top of mold, 3 to 5 hours.
Preheat oven to 370°F with rack in lower third. Place dough in mold on a baking sheet. Use a serrated knife to score an X across entire surface of dough. Place remaining 1 Tbsp. chilled butter in center of X and bake until a wooden skewer inserted into center comes out slightly moist but not wet, 1 to 1¼ hours. (Panettone will be very dark.)
Pierce skewers all the way through panettone (including paper) 4 inches apart and 1 inch from bottom so skewers are parallel. Hang panettone upside down over a large stockpot or between two objects of equal height and cool completely before cutting. Panettone keeps, wrapped tightly in foil in a sealable bag, at room temperature 1 week.