In a large bowl, combine whole wheat flour, 1 cup all-purpose flour, yeast, sugar, salt, herbs, onion, oil and water. Beat with an electric mixer on low until moistened, then beat for 3 minutes at medium. By hand, stir in enough of the remaining flour to form a stiff dough. Place in a greased bowl, turning once to grease top. Cover and allow to rise until doubled, about 1 hour. Punch dough down. Shape into two balls and place in two greased 2-qt. casseroles. Cover and let rise until almost doubled, about 45 minutes. Brush tops with milk and sprinkle with Parmesan cheese. Bake at 350° for 40-45 minutes. Remove from casseroles to cool on wire rack.