Heat heavy-bottomed pot over medium-high heat until a drop of water sizzles. Pat beef cubes dry and season with salt and pepper. Sear beef in batches 2-3 minutes per side until deep brown. Avoid crowding the pot. Transfer seared beef to a plate.
2 lbs beef chuck, salt, black pepper
Lower heat to medium. Add diced onions to pot with remaining beef fat. Cook 4-5 minutes until softened. Stir in minced garlic and tomato paste, cook 1 minute until fragrant and paste darkens. Pour in Guinness stout and scrape pot bottom with wooden spoon to lift browned bits.
2 large onion, 4 cloves garlic, 2 tbsp tomato paste, 1.5 cups Guinness stout
Return beef and any juices to pot. Add beef broth, thyme sprigs, and bay leaves. Liquid should nearly cover beef. Bring to gentle simmer (small bubbles breaking surface, avoid rolling boil), reduce heat to low. Cover pot and cook 1.5 hours, stirring every 30 minutes.
2 lbs beef chuck, 2 cups beef broth, 4 sprigs thyme, 2 bay leaves
Stir in carrots and celery. Cover pot again and simmer for another 45-60 minutes until beef is fork-tender and vegetables are cooked but still hold shape. If sauce seems thin, uncover pot for last 15 minutes to reduce.
3 carrots, 2 stalks celery
Turn off heat and let stew rest uncovered for 15 minutes, allowing sauce to thicken and flavors to settle. Remove thyme sprigs and bay leaves. Adjust salt to taste. Serve in wide bowls, optionally with crusty bread.
4 sprigs thyme, 2 bay leaves, salt
