Combine yeast and 1 tsp of sugar in 1/2 cup of the water and let stand until foamy.
In bowl of electric mixer whisk together the egg yolks, vanilla, grated lemon peel, salt, remaining sugar and the rest of the water. Add the yeast mixture and then use a wooden spoon to mix in 3 cups of the flour.
Cut up the 6oz. of butter and gradually incorporate it into the batter using the dough hook on the mixer. then gradually add the remaining flour. Knead the dough for 10 minutes at medium speed. Then knead the dough by hand for 1 minute on a lightly floured surface.
Form into a ball, put in a lightly greased bowl, cover with plastic wrap and let rise until doubled in bulk.
Butter or Pam your pannetone mold or use coffee cans for smaller loaves. Turn the dough out onto a lightly floured board and knead in the raisins and candied peel. Cut the dough into pieces for each pan and allow to double in size again.
Preheat oven to 400°, brush tops of loaves with melted butter and bake for 15 minutes. Reduce heat to 350°, brush again with melted butter and bake 45 to 50 minutes longer, brushing again with butter after 30 minutes. If top browns too fast, cover with aluminum foil.
Unmold onto a rack and brush the top and sides with the remaining melted butter.