In a large bowl, dissolve yeast and sugar in water. Cover lightly with a dish towel for 5 minutes, or until yeast looks foamy.
Add the eggs, milk, honey and salt. Then, add three cups of flour and butter. Gradually add a fourth cup of flour and mix briefly until dough is able to be handled.
Turn dough out onto a floured board and begin kneading, gradually adding a cup of flour, as needed, until the dough is smooth and satiny. This step should take about 10 to 15 minutes.
Place dough in a greased bowl and turn once to lightly grease the surface of the dough. Cover it tightly with plastic wrap, then let it rise until it doubles in size. This should take about one and a half to two and a half hours.
Punch down the dough, knead it five or six times in a bowl and let it rest for 10 minutes. Then, turn the dough out onto a lightly floured board and flatten it into a circle. Cut in half. Divide the first piece into thirds, squeezing and elongating strips for braiding. Braid and place on a lightly greased baking sheet. Repeat this step with the second piece of dough. Lightly cover the loaves and let them rise for approximately 30 to 40 minutes.
Mix two egg yolks with about a teaspoon of water. When the loaves are ready, brush them all over with the egg wash and sprinkle with seed seasoning (optional).
Bake at 375 degrees for 20 minutes. Then, turn the oven down to 350 degrees and bake for an additional 10 minutes, or until the loaves are brown (to your liking) and sound hollow when tapped. Cool on rack.