Heat the olive oil in a large heavy-bottomed pot over medium-high heat.
Pat the beef stew meat dry with a paper towel and season with the sea salt and black pepper.
Add the beef to the pot and sear until browned on all sides, then remove the beef and set aside.
In the same pot, add the diced onion, carrots, and celery, sautéing for about 5 minutes until the onions are translucent.
Stir in the tomato paste and dried thyme, cooking for 1 minute to wake up the aromatics.
Return the beef to the pot and pour in the beef broth, scraping the bottom of the pan to release any browned bits.
Add the diced potato, green beans, and the bay leaf to the liquid.
Bring the mixture to a gentle boil, then reduce the heat to low and cover with a tight-fitting lid.
Simmer for 45 to 60 minutes, or until the beef is fork-tender and the vegetables are soft.
Discard the bay leaf before ladling the hearty stew into deep bowls to serve.