Cook bacon, saving about 1/4 cup of drippings. Crumble bacon, reserving 4 or 5 strips for the top of dish. Saute onion in remaining drippings. Add cheese soup, milk, Wrocestershire sauce and mustard; mix well and heat through. Stir in the bacon, macaroni, shredded cheese and pimiento. Place in casserole dish (I use 3 quart). Top with remaining strips of bacon. Bake in a 375 degree oven for 25 minutes. Enjoy!!