Heat olive oil in a wide, heavy skillet over medium-high heat.
Add onion. Cook 5 minutes, stirring occasionally, until they begin to brown. Add garlic. Cook another minute.
While onions are cooking, coarsely chop the sliced mushrooms - no need to be exacting about this, just cut them up a little more. Add mushrooms to the skillet. Cook, stirring occasionally, until they have browned somewhat.
If desired, add a little wine to the pan, and boil vigorously until it has disappeared.
Add salt, pepper, seasoning and tomatoes. Allow the mixture to simmer on low heat about 10 minutes or until it has thickened.
Serve over long noodles such as vermicelli or spaghetti, or use any place red sauce is used (in lasagna, to cook chicken or beef,) etc.