Place the bowl of risen dough on the middle shelf of a cold oven. Place a casserole dish full of boiling water on the shelf underneath to create a warm, moist environment. Shut the oven door and let it prove for 1½ hours to warm it up and soften it.
You'll need two 6-inch springform cake pans that are at least 3 inches deep. You'll get a higher-rising loaf if you use a special panettone pan with 6-inch tall sides. Grease the pans lightly with butter. If you're using a shorter pan, line with parchment paper, and let the paper stick a few inches above the sides of the pan.
Stir the soaked fruit mixture, then dump it into a large mesh sieve set over a bowl. Any excess liquid will drain into the bowl.
Punch down the dough, then divide it in half. Place one half in the bowl of a stand mixer fitted with the paddle attachment. Add half of the dried fruit mixture, mixing on low speed until the fruit is evenly distributed. Repeat with the other half of the ingredients. (Feel free to do this step by hand if you don't have a stand mixer.)
Shape each piece of fruited dough into a ball and place in the prepared pans. Cover with plastic wrap and prove in the steamy oven until the top is level with the top of the tin. This will take about 1½ hours.
About 10 minutes before the loaves are done proving, take them out of the oven and preheat it to 400°F.
Press 5 blanched almonds in a star shape onto the top of each panettone. Bake the loaves at 400°F for 10 minutes, then lower the temperature to 375°F and bake for another 10 minutes. Lower the temperature again to 350°F and bake for 10-15 minutes. Cover the tops with foil if it is getting too dark.
Unclip the sides of the springform pans and remove the loaves from the pan. About 2 inches from the bottom of the loaves, poke three long skewers all the way through the loaf. Flip the loaf upside down and hang them over a large pot or mixing bowl. Repeat with the other loaf, then let the bread cool upside down for 1½ to 2 hours.
Remove the skewers, sprinkle with sifted icing sugar, cut in wedges, and serve with generous amounts of salted butter. Leftovers can be frozen for up to 3 months and defrosted at room temperature.