Spread ¾cup of oats on a microwave safe plate. Microwave on high power 1½~2 minutes, stopping to stir every 30 seconds, or until the oats are fragrant and lightly toasted. Cool.
In a bowl, mix 1½cups of water with 1 cup of ice cubes.
Combine bread flour, 1¼cups of whole wheat flour, salt, yeast and toasted oats in a large mixing bowl.
Measure 1½cups ice water into a measuring cup, add honey and oil and mix well to combine.
Vigorously stir in honey mixture into the flour mixture. Dough should be slightly stiff, add in just enough additional flour to stiffen dough slightly, if necessary.
Brush top of dough with oil.
Cover bowl with plastic wrap and let rise at room temperature for 8~12 hours.
Vigorously stir dough, scraping down bowl sides. Stir in remaining ¼cup of whole wheat flour. Stir in more flour if dough is at all soft, to have stiff but still stirrable dough.
Oil a 9″x5″ loaf pan, transfer dough to pan, and smooth the surface with a spatula or well oiled finger tips. Press remaining ¼cup oats on top of loaf. Cover with lightly greased plastic wrap.
Let dough rise 1¼~2½ hours at room temperature.
Preheat the oven to 375°F. Remove plastic wrap and bake loaf for 30~35 minutes or until the top is well browned. Cover with foil and bake for another 25~30 minutes more or until an instant read thermometer inserted into the center of the bread registers at least 190°F.
Cool in pan for 5 minutes before removing it onto a wire rack. Cool completely before slicing