Mix 2 cups flour, 2 cups milk, 1/2 cup starter, 2 Tblsps. sugar, 2 tsps. salt, and 1 tsp. baking soda in a large bowl. Beat until smooth.
Cover loosely with waxed paper. Let stand in a warm place 18 hours.
Add 2 Tblsp. oil and 1 pkg. yeast. Stir to blend. Mix in 3 to 4 cups flour to make a moderately stiff dough. Knead on lightly floured board until smooth and satiny.
Sprinkle work surface with cornmeal. Roll dough on cornmeal until dough is 3/8" thick. Cut with floured cutter.
Let rise until doubled. Grease a griddle and preheat to 275 degrees.
Bake muffins 10 to 15 minutes on each side, turning once to serve, split and toast.