1) The night before you want to make the bread, mix together the biga (overnight starter) ingredients. Cover the bowl, and leave it at room temperature for up to 15 hours or so.
2) Next day, combine the bubbly starter with all of the remaining dough ingredients except the grated orange rind and the fruit. Mix to combine. Switch to the dough hook, and knead for about 12 minutes at medium speed, stopping the mixer every 3 minutes to scrape the bottom and sides of the bowl. By the end of the kneading time, the dough should have become elastic and satiny. It should be starting to leave the bottom and sides of the bowl, though it won't form a smooth ball.
3) Knead in the grated orange rind and dried fruit.
4) Cover the bowl, and let the dough rise for 2 hours (3 hours if you're not using SAF Gold yeast). It should have become quite puffy.
5) Divide the dough in two pieces, with one slightly larger than the other. Shape one into a 10" log, with one tapered end; and the other into a 7" log.
6) Place the longest log lengthwise on a lightly greased or parchment-lined baking sheet; use the edge of your hand to form a crease in the center. Lay the shorter log crosswise across it, right at the crease. Shape the shorter log into "wings" by pulling it into a crescent shape. (We know, this doesn't really look too awfully much like a dove; think of it as a symbolic representation!)
7) Cover the shaped loaf with a cover or lightly greased plastic wrap, and set it aside to rise until it's puffy; this will take about 1 to 2 hours, depending on what type of yeast you've used. Towards the end of the rising time, preheat the oven to 375°F.
8) Make the topping by mixing the egg white, ground almonds, and sugar. Gently paint this glaze all over the loaf; be generous. Sprinkle with the sliced almonds, then the pearl or coarse sugar.
9) Bake the loaf for 15 minutes, then reduce the oven heat to 350°F and bake for an additional 20 minutes, tenting it for the final 10 minutes of baking. The finished loaf will be golden brown, and an instant-read thermometer inserted into the center will register 190°F.
10) Remove the bread from the oven, and carefully slide it onto a rack to cool.
11) Serve in thin slices. Some enjoy fresh Colomba with a glass of wine; some prefer it toasted, then drizzled with heavy cream or honey, and served with coffee. It's delicious just plain, too; serve it Easter morning, or later in the day, as a sweet accompaniment to the Easter ham.
Yield: 1 large loaf.