1 pkg. yeast
1 1/4 c. lukewarm water
4 to 4 1/2 c. unbleached white flour
1 egg
2 tsp. salt
2 tbsp. melted butter or oil
1 egg yolk
4 tbsp. sesame seeds

Dissolve the yeast in 1/4 cup lukewarm water and put it aside for a few minutes.

Pour 4 cups of white flour into a large mixing bowl. Add to it the egg, the yeast, the remaining water, the salt, and the oil or butter. Stir vigorously until the dough is smooth and somewhat elastic. Add a little more flour to make a stiff dough.

Turn the dough out onto a lightly floured board and knead until it is very elastic and smooth. Form the dough into a ball and put it into an oiled bowl, turning it over once so that all the surface is lightly oiled. Cover the bowl with a tea towel and set it aside to rise for about an hour; it should double in size.

Punch down the dough, knead it a few more turns, then form it into as smooth a ball as possible. With your fingers, poke a hole through the center of the ball. Pull apart the dough carefully into a donut shape, making it even and pulling up dough from the sides into a tightly pinched circular seam. Place the ring in a buttered pan, cover with a tea towel, and leave it to rise until nearly double.

Brush the top with beaten egg yolk and sprinkle a dense layer of sesame seeds over the entire visible surface of the loaf. Bake at 375 degrees for about 50 minutes. Serve with your finest Greek dinner.