Season the beef chuck cubes with salt and black pepper, then toss with the all-purpose flour until evenly coated. Brown the meat in batches in the vegetable oil over medium-high heat until deep golden on all sides, adding more oil if needed.

In the same Dutch oven, cook the chopped onion for 5 minutes over medium heat, scraping up any browned bits as they loosen. Add the minced garlic and tomato paste and cook for 1 minute until fragrant.

Pour in the Irish stout and scrape the bottom of the pot to lift the caramelized fond. Add the beef broth, dried thyme, dried rosemary, and bay leaves, then return the browned beef to the pot.

Cover and simmer at a gentle bubble for 1 1/2 hours, stirring once or twice so nothing sticks. Add the potatoes, carrots, and celery, then simmer for 45-60 minutes until the vegetables are tender and the stew looks thickened.

Remove the bay leaves and finish by stirring in the chopped fresh parsley. Taste and adjust seasoning if needed, then serve hot with a chunky, gravy-coated consistency.