Preheat your oven to 300°F (150°C).

Season the short ribs with salt and pepper on all sides.

In a Dutch oven, heat vegetable oil and sear the short ribs for 3-4 minutes on each side.

Sauté chopped onion, carrots, and celery for 5 minutes until softened.

Stir in minced garlic and cook for an additional minute.

Pour in beef broth and red wine, add tomato paste, Worcestershire sauce, thyme, and bay leaf. Bring to a simmer.

Return seared short ribs to the pot, ensuring they are submerged in the liquid.

Cover and braise in the oven for about 2.5 hours.

While ribs are braising, boil chopped potatoes in salted water for 15 minutes.

Drain potatoes, return to pot, and mash with milk and butter until smooth.

Serve short ribs on top of creamy mashed potatoes and drizzle with braising liquid.