Preheat oven to 350 degrees F.
Pat the short ribs dry and sprinkle with salt and pepper on all sides.
Heat oil over medium high heat in a large oven safe skillet or braising pan.
Adding a couple at a time so the pan isn’t crowded, sear the beef ribs, turning to sear all sides of the meat for 1-2 minutes. Remove and set aside, continuing until all ribs have been seared and removed.
To the pan add the carrots, onion, and celery. Sauté until tender.
Stir in tomato paste coating the vegetables. Pour in beef broth, stirring until combined.
Add in Worcestershire and mustard stirring to combine.
Taste sauce and adjust seasonings, adding salt as needed, approximately 1 tsp.
Place short ribs into the skillet with the sauce. Add in the fresh herbs (to make it easy to remove, tie the herbs together with food grade twine).
Cover and braise in the oven for 2.5-3 hours until meat is tender.
Remove the skillet to stovetop. Remove the short ribs to a plate or cutting board, cover with foil. Then continue to cook the sauce at a simmer over medium heat uncovered for 15-20 mins to reduce and thicken,
Serve the ribs over mashed potatoes and spoon sauce over the top.
Top with fresh herbs as a garnish.