Italian sausage in a creamy mushroom sauce

This is a recent creation of my husbands, and OH, is it ever good. You can put it over pasta, or just serve it by itself, as an hors d oeuvre. 1 T Olive Oil 1/2 red onion, diced 1/2 lb mushrooms, sliced 1 1/2 lb hot italian link sausage in 1 inch pieces 1/2 c flour 1/2 c sun dried or dehydrated tomatoes 4 c milk 1 clove garlic minced grated Parmesan or Romano to top(1/8 to 1/4 lb depending on taste) Saute onion in Olive Oil until soft add sausage and cook until almost done mix in flour to coat sausage add milk stirring until hot add mushrooms and garlic simmer for 5 minutes add tomatoes mix with pasta or serve as desired leave grated cheese on table for people to mix in as desired. NOTES the sauce is very thick and creamy The tomatoes really just add a bright note to this dish Roux, who needs a traditional roux. Before I was able to make one properly I coated what I sauteed with flour and found I didn't have any lumps.