Dissolve the fresh yeast in the warm milk in the bowl of a stand mixer and let it stand for 5 minutes until slightly foamy.

Add the flour and sugar to the yeast mixture and begin kneading on medium speed with the dough hook for 3 minutes until a rough dough forms.

Add the egg yolks one at a time, waiting for each to incorporate before adding the next.

Add the softened butter in three additions, kneading on medium-high speed for 8 to 10 minutes total until the dough is smooth, slightly tacky, and pulls away cleanly from the bowl sides.

Shape the dough into a ball, place in a lightly oiled bowl, cover with plastic wrap, and refrigerate overnight for 10 to 12 hours.

Take the first dough out of the fridge and let it come to room temperature for 1 hour - it should have roughly doubled in size.

Place the first dough back in the stand mixer bowl. Add the flour, warm milk, sugar, honey, vanilla, and salt. Knead on medium speed for 5 minutes until combined.

Add the egg yolks one at a time, incorporating each fully before the next.

Add the softened butter in five or six small additions on medium-high speed. Take your time - each addition should disappear into the dough before the next goes in. Knead for 10 to 12 minutes total until the dough passes the windowpane test.

Reduce the mixer to low and fold in the drained raisins, candied peels, and citrus zests. Mix only until evenly distributed, about 1 to 2 minutes.

Cover the bowl with plastic wrap and leave at room temperature (around 24 to 26 C) for 1 hour as a short bench rest.

Turn the dough onto a lightly floured surface. Fold the edges toward the center three or four times to build surface tension, then flip the dough and roll it gently against the work surface using cupped hands until you have a smooth, taut ball.

Place the dough ball seam-side down into the 1 kg paper panettone mold.

Cover loosely with plastic wrap and leave to proof at room temperature (24 to 26 C) for 4 to 6 hours, until the dough has domed 2 to 3 cm above the rim of the mold. Do not rush this step.

Heat the oven to 180 C / 355 F (conventional, not fan). Place a rack in the lower third.

Using a sharp, lightly oiled blade, score a shallow X across the top of the panettone. Place the 10 g cold butter knob in the center of the X.

Bake for 40 to 45 minutes until deep golden brown and a probe thermometer inserted into the center reads 93 to 95 C. If the top colors too quickly after 20 minutes, tent loosely with foil.

Remove the panettone from the oven. Immediately push two long metal skewers through the base of the mold in a cross, just above the bottom. Invert the panettone and suspend it upside-down between two tall pots or heavy books, allowing it to hang freely. Leave it inverted for at least 3 hours or until fully cool.

Remove the skewers, wrap in plastic wrap, and store at room temperature.