1 pkg. active dry yeast
1 1/2 c. warm water
5 1/2 - 6 c. flour
1 c. sour dough starter (room temp.)
2 tsp. salt
1/2 tsp. sugar
1/2 tsp. baking soda

In large bowl soften yeast in warm water. Blend in 2 1/2 cups flour, starter, salt and sugar. Combine 2 1/2 cups flour and baking soda, stir into flour-yeast mixture. Add enough remaining flour to make a stiff dough. Knead 5 to 7 minutes. Shape in ball. Place in greased bowl; turn once. Cover and let rise in warm place until double. Punch down; divide in half. Cover and let rest 10 minutes. Shape into 2 round loaves. Place on lightly greased baking sheets. With sharp knife, make diagonal slashes across tops of loaves. Let rest in warm place until double. Bake at 400 degrees for 35 to 40 minutes. Remove from baking sheets; cool.