1. Season
the chicken pieces generously with salt and pepper. Dredge the pieces
in flour, coating them lightly and tapping off excess flour.
2. In
a wide (at least 12-inch) 5 quart, frying pan, heat the vegetable oil
with 2 tablespoons of the olive oil until a piece of chicken dipped in
the oil gives off a very lively sizzle. Add as many pieces of chicken
to the pan as will fit without touching. Do not crowd chicken; if the
skillet is not wide enough to fit all of the chicken, brown it in
batches.
3. Remove chicken pieces from the skillet as they brown, adding some of the remaining pieces of chicken to take their place.
4. Remove all chicken from the skillet. Leave about 2 tablespoons of the oil and add the onion and cook,for about 5 minutes.
5. Pour the wine into the pan, bring to a boil, and cook until reduced by half, about 3 minutes.
6. Add the tomatoes and oregano, season lightly with salt and pepper, and bring to a boil.
7. Add chicken to the sauce, adjust the heat to a gentle boil, and cover the pan. Cook, stirring a few times, 20 minutes.
8. In a large skillet, heat the remaining 2 tablespoons olive oil over medium-high heat.
9. Add
the mushrooms and peppers, and toss until the peppers are wilted but
still quite crunchy, about 8 minutes. Season the vegetables with salt.
10. Stir
the peppers and mushrooms into the chicken pan. Cook covered until the
chicken and vegetables are tender, 10 to 15 minutes. Check the level of
the liquid as the chicken cooks. There should be enough liquid barely
to cover the chicken. If necessary, add small amounts of water to
maintain the level of liquid as the chicken cooks.