Place ¼ cup of the flour in a medium bowl. Using paper towels, pat the stew meat as dry as possible, then season generously with the salt and ground black pepper. Dredge the seasoned stew meat in the flour, coating the meat well but shaking off any excess flour. Set aside.
Add the olive oil to a large heavy-bottomed pot over medium-high heat (I use a 5-quart Dutch oven). Once the oil & hot and shimmering, add in the beef, shaking off any excess flour before adding it into the pot. Brown 2-3 minutes per side, working in batches as necessary to avoid overcrowding the pot.
Once the beef is browned, add the remaining ingredients into the pot: celery, carrots, onions, potatoes, tomato paste, tomato sauce, shoyu, Worcestershire, & 3 ½ cups of the beef stock. Stir to combine.
Increase the heat to high to bring the mixture to a boil. Reduce to low to maintain a gentle simmer. Cover & simmer for 2-3 hours, stirring occasionally, until the beef is fall-apart tender. Add the remaining ½ cup beef stock & ¼ cup all-purpose flour to a bowl or jar, whisking or shaking vigorously to combine until a slurry forms. While stirring, gradually pour the slurry into the beef stew. The stew should thicken almost immediately. Simmer 1-2 minutes longer to cook off the flour.
Fill in some text