Coat a large bowl with vegetable shortening or cooking spray. Set aside.
Add yeast to 1/4 cup warm water; let stand 10 minutes.
In another large bowl combine buttermilk, sugar, honey, butter, salt, and oat bran cereal. Let rest 5 minutes. Stir in egg, oat bran flour and softened active dry yeast. Add rest of flour to make soft dough.
Turn onto a lightly floured surface and knead until smooth (10 minutes by hand or 4 minutes in an electric mixer or food processor fitted with dough hook). Place in the prepared bowl, turning once to grease the top of dough. Cover with a clean cloth and let rise in a warm draft-free place until doubled; 1 to 1-1/2 hours.
Coat 9x5 –inch loaf pan lightly with vegetable shortening or nonstick cooking spray.
Knead dough for 30 seconds. Shape into a loaf and place in loaf pan, turning once to coat top with shortening. Let rise in warm place until doubled; 40 to 50 minutes.
Preheat oven to 350°F. Bake 30-35 minutes. Remove bread from pan immediately and cool on rack.