Sprinkle yeast into water in large bowl. Scald milk, add 1/2 cup butter & salt and cool to lukewarm.
Meanwhile, beat eggs & sugar until light. Add milk mixture to eggs, then stir into yeast mixture. Gradually beat in 3 cups of flour with a wooden spoon. Stir in enough additional flour to make a soft dough that is workable & leaves the side of the bowl.
Turn dough out onto a lightly floured board & knead (10 min.) add additional flour as necessary. Knead until dough is smooth and elastic. Put dough in lightly greased bowl, turn once to grease top. Cover, let rise in warm, draft-free place for 1 to 1 1/2 hours until doubled in bulk. Punch down, let rest for 10 min.
Divide dough into thirds, shape each into a ball. Flatten each ball (use hands) to 8-9 in. diameter. Press into 3 greased round 9" layer cake pans. Cover and let rise in warm, draft-free place about 1 hr. until doubled.
Put Pizza Stone in oven. Preheat oven to 375. Place pan on the stone (you will only be able to accommodate one pan at a time on the stone). Bake for approx. 30 min., or until well browned. Brush with melted butter while still hot. Cool.