In a large sauce pan, heat the olive oil over low heat. Add the onions and garlic and gently saute for about 5 minutes until they begin to soften. Add the flour and stir into the veggie mixture with a wooden spoon.
Add the white wine and milk, and stir. Bring to a simmer and gently simmer for 3 or 4 minutes until the sauce begins to thicken. Add the salt, parmesan, and parsley, and stir until cheese begins to melt. Serve with pasta of choice, sauce makes enough for about 1 lb of pasta.