In a large mixing bowl, to half the flour (1 cup) add the remaining ingredients and mix together with a rubber spatula until just blended. Sprinkle the remaining flour over the top, cover bowl with plastic wrap, and let sit for at least one hour, up to four. The sponge should rise and crack through the flour coating.
The First Mixing and Incorporating the Butter:
Place 1 cup of flour to the mixing bowl and add the sugar, eggs, and salt. Mix on low for one minute, until the ingredients start to join. Sprinkle in about ½ cup more of flour while still beating on low. When this flour is incorporated, raise the speed to medium and beat for 15 more minutes. If your mixer starts to overheat, you can do this gradually, in 2-3 minute sessions. After about 6-8 minutes, if you don’t have a cohesive dough that slaps against the sides of the bowl, add up to 3 tablespoons more of flour.
Now comes the fun part. Before you add the butter to the dough, the consistency of both must match. In other words, you have to beat the butter. I prefer a French rolling pin and wax paper. Place the butter between two sheets of wax paper and use the pin to roll it into submission until it’s flat and soft but still cool. If it gets oily and too warm, put it back in the refrigerator for a few minutes to cool it down.
Gradually, a few tablespoons at a time, add the butter to the dough with the mixer on medium low. When butter is added to this smooth dough, at first it will fall apart but as you add the rest of the butter, with more beating, it will all come together. Beat the dough for an additional 5 minutes, scraping down the sides of the bowl as the beater works and slaps the dough against the bowl. If the dough just isn’t coming together, try adding another tablespoon of flour. Even at this point the dough should feel cool, soft and sticky, clinging slightly.
Butter a large bowl and transfer the dough, covering tightly with plastic wrap. Let rise for 2-3 hours, depending on the temperature of the room.
After the dough has doubled, gently deflate it by turning it a few times in the bowl. Cover again and place it in the refrigerator, letting it rise for 4-6 hours (or even overnight). It should double again in size.
The Egg Wash:
Butter or spray three 8 by 4 or 8 ½ by 4 ½ bread pans. With a dough scraper on a lightly floured surface, divide the dough into three equal pieces.
Repeat to make six pieces in total. If you wish to make smaller loaves, divide the original three pieces into 4 or 6 equal pieces, for a total of 12 or 18 small loaves. I prefer larger loaves because of their versatility.
Shape each piece into a ball and place two of them in each loaf pan, side by side. They will be touching. Cover the pans with two towels, the bottom one dry, the top one a bit moist (or buttered plastic wrap), and let them rise at room temperature, for about two hours, until doubled in size.
Preheat an oven to 375°.
Then, brush the tops of each sparingly with the egg wash, making sure the dough is washed but not spilling it into the sides of the pans, so the dough will continue to rise in the oven and won’t be difficult to remove. With a pair of kitchen shears, quickly snip an X or cross into the top of each loaf and bake for 30 minutes until golden brown. If they brown too quickly, cover very loosely with foil until they are done. Remove from the oven and let sit in the pan for a few minutes before removing them gently. They are best they day they are made, but if you make larger loaves, you can slice them the next day for French toast.