How to Make It
Dissolve yeast in 1 cup warm water and milk in a small bowl; let stand 5 minutes.
Weigh or lightly spoon flour blend and flaxseed meal into dry measuring cups; level with a knife. Place flour blend, flaxseed meal, oats, and next 3 ingredients (through baking soda) in a large bowl, stirring with a whisk. Slowly add yeast mixture, honey, butter, vinegar, and egg yolks, beating with a mixer at low speed. Increase speed to high; beat 1 to 2 minutes until well blended.
Place egg whites in a bowl; beat with a mixer at high speed until soft peaks form using clean, dry beaters. Gently fold egg white mixture into batter. Spoon batter into a 9 x 5-inch loaf pan coated with cooking spray. Cover with plastic wrap, and let rise in a warm place (85°), free from drafts, 1 hour or until dough is just above top of pan.
Preheat oven to 375°.
Bake at 375° for 10 minutes. Cover with foil; bake an additional 35 minutes or until very browned. Cool 10 minutes in pan on a wire rack; remove from pan. Cool completely on wire rack.