Pat the beef cubes dry with paper towels and season generously with salt and pepper. Heat olive oil in a large Dutch oven over medium-high heat. Working in batches, sear the beef on all sides until a deep brown crust forms. Remove beef to a plate.

Reduce heat to medium, add butter to the pot. Add the chopped onion and cook until soft, about 5-7 minutes. Add minced garlic and dried thyme, cooking for another minute until fragrant.

Sprinkle the flour over the onions and stir for 1 minute. Slowly whisk in the beef broth and Worcestershire sauce until smooth. Scrape up any browned bits from the bottom of the pot.

Return the seared beef and any juices to the pot. Bring to a simmer, then reduce the heat to low, cover, and cook for 1.5 to 2 hours, or until the beef is fork-tender.

Taste the gravy and adjust seasoning with more salt and pepper if needed. Serve hot over mashed potatoes, egg noodles, or rice.