Dissolve the yeast in water, add the flour, and mix well. Cut a cross on top and let it rise for 4 to 6 hours in the oven with the light on (oven turned off).

Dissolve the starter in warm water directly in the bowl of a stand mixer. You can discard any leftover starter.

Sift both flours and add them to the dough one spoonful at a time, waiting for each addition to be absorbed before adding the next.

With the mixer running, add the egg yolks, then the sugar. Finish by adding the butter cut into cubes and let the mixer knead for 20 minutes. After that, cover the bowl with plastic wrap, wrap it with a towel, and let it rise overnight.

Soak the raisins in hot water.

Next, add the sugar, then the egg yolks one at a time, the orange zest, and the melted butter, making sure each ingredient is fully incorporated before adding the next. Knead for 15 minutes.

Drain the raisins, squeeze them well, and add them to the dough while mixing on the lowest speed.

Transfer the dough to a lightly floured work surface and start folding it.

Remove the panettone from the oven and let it sit until a crust forms, about 30 minutes.

Score a cross on top with a razor blade and place 2 tablespoons (30 grams) of butter, cut into pieces, in the center.

Remove the pot of water from the oven and preheat to 375°F (190°C), conventional mode. Once the oven is hot, bake the panettone. After 7 minutes, open the oven door to release steam, lower the temperature to 350°F (180°C), and bake for another 30 minutes. If it browns too quickly, cover the top with aluminum foil. When done, remove the panettone and, using two knitting needles, pierce it and hang it upside down for one night (about 24 hours) to cool completely.