1 pkg. active dry yeast
1 1/2 c. warm water
5 1/2 to 6 c. all purpose flour
1 c. sourdough starter (room temp.)
2 tsp. salt
2 tsp. sugar
1/2 tsp. baking soda

In large mixer bowl, soften yeast in warm water. Blend in 2 1/2 cups of the flour, sourdough starter, salt, and sugar. Combine 2 1/2 cups of the flour and the baking soda; stir into flour, yeast mixture. Add enough remaining flour to make a stiff dough. Turn out onto a lightly floured surface and knead until smooth and elastic (5 to 7 minutes). Shape in ball. Place in greased bowl; turn once. Cover and let rise in warm place until double (about 1 1/2 hours). Punch down; divide in half.

Cover and let rise 10 minutes. Shape into 2 round loaves. Place on lightly greased baking sheets. With sharp knife, make diagonal slashes across tops of loaves. Let rise in warm place until double (1 1/2 hours). Bake 400 degrees for 35 to 40 minutes. Remove from baking sheets; cool. If desired, brush with butter. Makes 2 loaves.