Pre heat oven to 325 degrees.
Dry Short Ribs with a towel, season with salt & pepper, coat with flour, and lightly brown in oil on all sides over medium heat in large sauté pan.
When brown, transfer ribs to a large casserole pan with high sides so there is room for liquids and ribs.
Add oil if necessary and lightly brown garlic, shallots and onion for one minute. Stirring, add carrots and celery. Brown and stir for one minute more. Add one T. flour to vegies, stirring. Add approx. one cup of port to pan and scrape bits and pieces from the bottom of the pan.
Scrape and transfer to casserole with the ribs. Add remaining port to casserole, beef broth, and mustard, Worcestershire, tomato paste, thyme and bay leaves, place casserole on stove and bring to simmer.
Cover with foil and braise in oven for four hours.
Carefully remove casserole from oven and lift foil off (careful of steam burn). Transfer ribs to platter, strain liquid into sauce pan and reduce if necessary. Should be thick enough to coat spoon. Simmer for two minutes, try to skim fat off of top. If it’s too thick add broth or red wine. If it’s too thin reduce faster at higher heat, it’s great to have about two cups of sauce at this point.