Place the flour, salt and pepper into a Ziploc bag. Toss the beef cubes in the flour until well coated.
In a large Dutch oven, heat the oil over medium heat. Place the floured beef cubes into the oil, in one layer. Cook, turning the beef, until browned on all sides.
If you want to use the homemade beef stew seasoning, omit the thyme, rosemary, parsley, and garlic in the next step. Add two tablespoons of the seasoning mix, then continue with the Worcestershire, and tomato paste.
Add in the beef broth, scraping any browned bits off of the bottom of the Dutch oven. Stir in the thyme, rosemary, parsley, garlic, Worcestershire, and tomato paste. Bring to a boil, then reduce heat, cover, and cook for 2 hours in the oven.
Add the potatoes, carrots, celery, and onion to the pot. Cover and cook for another 1-2 hours in the oven or until the vegetables are tender. Add in the peas for the last 5 minutes and heat up.
If desired, prepare dumplings and place on top of the stew. Close and cook for 20 minutes. Remove from the oven and remove the lid. Let sit for about 5 minutes then serve.