We will begin preparing a sponge the day beforer. For that, in a bowl we put 200 g of the flour, the water and the yeast dissolved in it. Stir with a wooden spoon, cover with plastic or a cloth and let rise slowly in the fridge for 12 hours.
The next day, we took the sponge out of the fridge and let it temper for an hour in a warm place from the kitchen. Next, in the bowl of a robot kneader or in a bowl if we are going to knead by hand, add the remaining flour, the sponge, the two beaten eggs and yolk, the inverted sugar and the powdered milk. Knead for 10 minutes, let the dough rest for five minutes.
Add the sugar, and the orange zest and we knead another 10 minutes, we rest another five. We do the membrane test to verify that the kneading is correct, that is, we stretch a ball of dough with our fingers and see that it forms a fine veil of dough that does not break. Then we add the butter in small pieces and the salt, we knead another 10 minutes. We check the dough again.
Carefully stretch the dough into a rectangle and add the candied fruits and raisins, turning it a few times until we integrate them into the dough. We roll the dough and leave it in a floured bowl and covered with a cloth or film until it rises in a warm place away from drafts.
Once risen, we degas the dough with our knuckles and round it again and place the ball in a paper mold of one kilo of panettone or it can be divided into two 500-gram buns if we want smaller buns. Let rise again inside the mold until it reaches the edge of the paper moldThis can be up to 5 or 6 hours later if the kitchen temperature is around 18 degrees. Paint with beaten egg and add a little sugar moistened with a few drops of water and a ball of butter.
We preheat the oven to 180 degrees, bake on the lower deck for 40 minutes. Once cooked, we pass a knitting needle through the base and hang it upside down until it cools.