Preheat your oven to 350°F (175°C).
Season the beef short ribs generously with salt and pepper.
Heat olive oil in a large oven-safe pot over medium-high heat.
Sear the ribs on all sides until browned, about 3-4 minutes per side.
Remove the ribs and set aside.
In the same pot, add chopped onion and cook until translucent.
Add minced garlic and sauté for another minute.
Stir in tomato paste, cooking for 1-2 minutes.
Pour in red wine, scraping the bottom of the pot to deglaze.
Add beef broth and thyme, then return the ribs to the pot.
Bring to a simmer, cover, and transfer to the oven. Cook for 2.5 to 3 hours until tender.