In a warm bowl dissolve yeast in warm water. Add salt, melted butter (cooled), and flour.
Using stand mixer with dough hook mix ingredients, on low speed, for one minute. Allow to rest for 2-3 minutes.
Continue to knead for 2 more minutes on low speed until dough is firm and no longer sticky.
Place dough in greased bowl, turning to grease the dough. Cover with plastic wrap and allow to rise for 1 hour. Dough should increase 1.5-2 times.
Deflate dough and turn on to floured surface. Pat dough flat into a rectangular shape and fold into three sections as you would a letter. Repeat 2 times.
Return to bowl, smooth side up and cover with plastic. Allow to rise for at least 1-1.5 hours. Dough should increase 2.5-3 times.
Cut dough into two equal parts and shape each into a round loaf making sure that you create sufficient surface tension on the top of the loaf. Gather the dough at the bottom as you shape the loaf, pinching the dough together on the bottom and forming a seal. Place both loaves bottom side up on a floured linen towel and cover with another floured linen towel. Allow to rise for an additional 1-1.5 hours.
Note: all rises should be in a fairly warm place (70-75F).
Place an oven proof skillet at the bottom of oven.
Preheat oven to 475F, then reduce to 450°F.
Place bread on parchment paper and, with very sharp knife, cut a cross into the top about 1/2 inch deep.
Slide parchment paper with loaf into oven on a pre-heated baking stone. Immediately pour 1/2 cup water into skillet to produce necessary steam. (Check you oven's instructions to make sure that this will not damage your oven.).
Bake for 20 minutes. Then check bread to be sure it isn't getting too dark. Continue baking for another 15 minutes.
Check internal bread tempeature with thermometer. If it has reached 200F then it's finished.
If not finished, reduce to 400F andbake an additions 8-10 minutes. Check temperature again.