In large bowl, sprinkle 1 package of dry yeast over 1 cup warm water. Let dissolve 5 minutes, then stir in 2 tablespoons of sugar, 1 1/2 cups sourdough starter, and then gradually add 4 cups of all-purpose flour mixed with 2 teaspoons of salt. Cover bowl with a damp towel; let rise 1 1/2 hours in warm place.

On a floured board, work in the dough, 1 cup flour until dough is no longer sticky. Knead until satiny (5 minutes). Shape dough into 1 large round or 2 long oval loaves. Put loaves on a cookie sheet sprinkled with rice or cornmeal. Let rise again in warm place for about 1 to 1 1/2 hours. Put shallow pan of water on lower shelf of oven. Preheat oven to 400 degrees. Make diagonal slashes across bread. Bake 40 to 50 minutes until crust is medium to dark brown.