Pat the stew meat dry and season generously with salt and pepper. Toss with the flour until every piece is evenly coated.
Heat the olive oil in a large Dutch oven or heavy pot over medium-high heat. Working in batches, sear the floured beef pieces on all sides until deeply browned. Do not overcrowd the pan. Remove and set aside.
Add the diced onion, chopped carrots, and chopped celery to the same pot. Cook for 4 to 5 minutes, stirring occasionally, until softened.
Add the tomato paste and stir it into the vegetables. Cook for 1 to 2 minutes until the paste darkens slightly and smells caramelized.
Add the Worcestershire sauce, thyme, and rubbed sage. Stir to combine.
Return the seared beef to the pot. Pour in the beef broth and stir everything together, scraping up any browned bits from the bottom of the pot.
Bring to a boil then reduce the heat to low. Cover and simmer for 1 hour.
Add the diced baby potatoes. Cover and continue simmering for another 30 to 45 minutes until the potatoes are tender and the beef is fall-apart soft.
Taste and adjust salt and pepper as needed. Serve hot.