While the sponge is bubbling, combine the milk and butter in a saucepan, heat to melt the butter and the scald the milk (see photo #2). Let cool to room temperature.
Once the sponge is bubbly (see photo #2), Add about one-third of the butter/milk mixture, one-third of the eggs, one-third of the sugar, a little less than one-third of the flour, and the salt. Begin mixing with your hands (see photo #3) until combined.
Add another third of each of the ingredients and mix with your hands until combines. The dough may start coming together a little more at this point (see photo #4).
Add the remaining butter/milk, eggs, sugar, and gradually add the flour, kneading until the dough pulls away cleanly from your fingers (see photo #5) and the sides of the pot (see photo #6).
Knead in the desired amount of raisins (see photo #7).
Put the lid on the pot and allow to rise in a warm place for about 2 1/2 hours, or until at least doubled in size (see photo #8).
Punch down and raise for another 1 1/2-2 hours, or until again at least doubled in size.
Punch down, then divide the dough into four high-sided about 9-inch diameter round pans (from what I have seen, I think tube pans will also work, but we don't do that). If desired, set aside a small amount of the dough, then use this to add decorations to the tops of the loaves. Since it is Easter, we make crosses on a couple of the loaves.
Lay towels over the loaves and let raise in the pan for about an hour.
Preheat the oven to 350°F.
Brush the tops of the loaves with the egg wash, and bake (typically two loaves at a time will fit nicely in the oven at once) for about 45 minutes, or until golden brown, and sound hollow when lightly tapped (see photo #9).
Allow to cool completely before removing from the pans. Then slice and serve (see photo #10).