Mix 4 cups of the flour with the remaining ingredients with a fork until mixed. Sprinkle 1/4 cup of flour on a board and turn out dough. Knead flour in until it forms a smooth dough. (Add more flour as needed). Grease a 9" round skillet or cake pan, dust with flour, then press loaf into pan. Cut a 1/2 inch deep cross in top of loaf. Bake 1 hour and 15 minutes at 375 degrees, or until it sounds hollow. Remove from pan to a wire rack; rub with butter and sprinkle with sugar. Cool completely.