How to Make It
Lightly spoon bread and oat flours into dry measuring cups; level with a knife.
Combine 3/4 cup bread flour, warm water, and yeast in a large bowl; stir well with a whisk. Cover and let stand at room temperature 1 hour.
Combine oats and boiling water in a small bowl. Stir in raisins, honey, and cinnamon; cool. Set aside.
Add 2 1/2 cups bread flour, oat flour, barley flour, salt, and vinegar to yeast mixture. Add oatmeal mixture; stir until a soft dough forms (dough will feel tacky). Turn dough out onto a lightly floured surface. Knead dough until smooth and elastic (about 10 minutes); add enough of remaining bread flour, 1 tablespoon at a time, to prevent dough from sticking to hands. Shape into 2 (9-inch) oval loaves. Make 3 parallel cuts 1/4-inch-deep across tops of loaves using a sharp knife. Place loaves on a baking sheet coated with cooking spray. Spray tops with cooking spray. Cover and let rise in a warm place (85°), free from drafts, 30 minutes or until doubled in size. (Press two fingers into dough. If indentation remains, the dough has risen enough.)
Preheat oven to 375°.
Uncover dough. Bake at 375° for 30 minutes or until the loaves sound hollow when tapped. Remove from baking sheet; cool on a wire rack.