Lightly flour turkey breasts, shaking off the excess. In a large heavy skillet, heat the vegetable oil over moderately high flame. Add turkey breasts in 2 batches and saute, turning once, until brown. Remove from the skillet and keep warm.
Wipe skillet clean and add 1 tablespoon olive oil. Add the onion and saute until onion is translucent. Add the butter, wine, peppers, zucchini and peas and saute for 2 minutes, then add chicken stock and bring to a boil. Reduce the heat and simmer sauce until well blended and thickened, for about 5 minutes.
Return the turkey to the skillet and cook for and additional 5 minutes. Season with salt and pepper. Arrange 2 pieces of turkey on each plate and spoon the sauce and vegetables over them.