With your fingers, rub the sugar together with the lemon and orange zest until you get moist and scented sugar. This can be done on the spot or 2 to 8 hours before you start mixing the dough.
In a stand mixer fitted with a paddle attachment, beat the sugar with the soft butter until pale and fluffy.
Add the honey, the orange blossom water, and the egg yolks and combine. Then add the eggs one at a time, mixing well between each addition.
Scoop out small pieces of the sponge and add them to the mixture while mixing on low speed until combined.
Add the flour and the salt and combine. Switch the paddle attachment for the hook and start kneading for 10 minutes at low speed. (It can also be done by hand). Transfer the dough to the counter and finish kneading by hand for 10 minutes until the dough is smooth.
Make two same-size buns, place each in a bowl lightly oiled, cover, and let rest in a warm place until they double their size. Approximately 2 hours.
Once they have grown, roll the dough on the counter with a rolling pin to get two rectangles of ¼ inch thickness.
Distribute the fruits and nuts on both rectangles, spreading them over the entire surface of the dough. Roll up and cut each of the rolls in half. We will obtain 4 rolls. Each one will be a panettone.
Cut each roll into slices and stack the slices switching positions. Take the stack with your hands and form a bun. Repeat with each of the rolls and place each one in the molds. Place the molds on a baking tray.
Cover lightly with plastic wrap and let rise again for 1 1/2 to 2 hours, until doubled in size.
For the egg wash, mix the egg white with the icing sugar with a fork or small whisk. Brush each of the loaves with the egg wash.
Bake the loaves in a preheated oven at 160°C or 320°F for approximately 40 minutes, until a toothpick inserted in the center comes out dry. In the case of using a thermometer, the inside of the bread should be at 78°C or 170°F. Remove from oven and allow to cool before decorating.