French Sourdough Bread

1 cup of sour dough starter
1 package of dry yeast
1 1/2 cup of warm water (110ºF.)
2 cups of flour
3 tablespoons of sugar
2 tablespoons of butter, melted
2 teaspoons of salt
1 cup of flour
1/2 teaspoon of baking soda
1 1/2 - 2 cup of flour

Let starter come to room temperature. Soften yeast in warm water, beat in 2 cups flour, sugar, butter, starter, and salt. Beat until smooth and add 1 cup flour to which baking soda has been added. Stir and add enough flour (1 1/2 to 2 cups) to make a moderately stiff dough. Knead on a floured board for about 8 minutes until smooth and elastic. Place in large greased bowl. Turn so greased side of dough is up, cover lightly with wax paper, let rise in warm place until double in size, about 1 to 1 1/2 hours. Punch down dough, divide and shape into 2 loaves. Place on cookie sheet that has been greased and sprinkled with cornmeal. Using very sharp knife make diagonal slashes 1/4" deep every 2" on loaves. Cover lightly. Let rise in warm place until double in size. Bake for 30 to 35 minutes at 375ºF. Brush loaves with warm salt water (1 teaspoon salt to 1/2 cup water) before baking, then several times during last 10 minutes. Cool on rack. May use whole wheat flour.