In a large nonstick dutch oven heat the oil then add the onion, bell pepper and garlic.Cook until softened ( 8 minutes or so) then add the turkey, breaking it up with a wooden spoon. Cook until the liquid evaporates and the turkey begins to brown.
Add the tomatoes, eggplant, mushrooms, salt and pepper and bring to a boil.
Reduce the heat and simmer uncovered, stirring occasionally for about 20 minutes.
Stir in the oregano and simmer until the eggplant has softened, about 10 minutes.