For the Starter: Stir the yeast into the lukewarm water and let it sit for about 10 minutes until frothy. Place the flour and salt in the bowl of a stand mixer with the dough hook attachment (if your bowl is too large for that small of quantity knead it by hand). Add the yeast mixture to the flour mixture and knead for 5 minutes if using the stand mixer and about 10 minutes if kneading by hand. Shape the dough into a ball and put it in a very lightly greased bowl, cover loosely with plastic wrap and let it rise at room temperature until doubled in size. Punch it down, cover with plastic wrap again and refrigerate it overnight. The next day take it out and let it come to room temperature before proceeding (this will take about 2 hours). Let it rise until nearly doubled in size.
To Prepare the Fruit Mixture: Place the raisins, candied lemon peel, candied orange peel, lemon and orange zest in a small bowl and pour 1/4 of hot water over them. Stir, cover and let soak for at least 2 hours or overnight. Drain any excess liquid before adding it to the panettone dough.
To Prepare the Panettone: Place the flour, yeast, salt and sugar in the stand mixer and stir to combine. Attach the dough hook attachment. Add the egg yolks and milk and mix until it comes all comes together. Punch down the starter dough and add it to the stand mixer. Knead it for 5 minutes, regularly scraping down the sides. Add the softened butter, vanilla and honey and knead for another 10 minutes (yes, that's 10 minutes). The mixture should be totally smooth and elastic but not overly sticky. Add the fruit mixture and knead until fully incorporated. Scrape the dough down, cover the bowl loosely with plastic wrap and let it rise at room temperature until nearly tripled in size, about 3 hours. Towards the end of this final rise preheat the oven to 350 degrees F (325 if using convection) and place the rack in the lower third of the oven.
Gently punch down the dough, form it into a ball and place it in a buttered panettone mold (7.3" x 4.25", click link for reference). Cover it loosely with plastic wrap and let it rise for about another 2 hours or until doubled in size. It should be risen to about 1 inch or so higher than the rim of the mold. Once the panettone is risen, if you'd like a glossy top brush the top of the panettone with some egg wash (a lightly beaten egg).
Use a very sharp knife (I use a razor blade) and score an "x" across the entire top of the panettone. Place about a tablespoon chunk of butter in the center. Bake the panettone for 40-60 minutes or until a toothpick inserted into the center comes out clean (if the top is browning too quickly place foil over it). Be careful not to over-bake or the panettone will be very dry.Recommended: For best accuracy and to prevent under or over-baking use an instant read thermometer. The panettone is done when the internal temperature reaches between 190 and 195 degrees F.
Remove the panettone from the oven and immediately stick two wooden skewers through the bottom of it and hang it upside down inside of a large, deep pot or somewhere where it can hang as it cools. This will prevent the top of the panettone from collapsing in on itself. Once cool, slice the panettone vertically in slices. Enjoy at room temp or toasted. See blog post for serving recommendations. Stored tightly wrapped in plastic wrap it will keep at room temperature for a few days to up to a week. It is best eaten within 2-3 days.