In a bowl, combine hot water, butter, sugar and salt. When butter melts, cool to warm and add yeast.
Cover in warm place until bubbly, about 15 minutes.
Add 5 cups flour and beat to form thick batter.
Stir in enough flour to form stiff dough, about 3 1/2 cups.
Let rise until double, about 1 1/2 hours.
Cut a circle of foil to fit into the bottom of a cast iron pan or aluminum dutch oven, 5 qt size.
Grease inside of dutch oven cover.
Punch down dough and place dough in pan and cover with lid. Let rise until the dough pushes up the lid 1/2 inch, about 1 hour. Watch closely.
Bake covered at 375º for 12 minutes, then remove the lid. Bake another 30 to 35 minutes.