Set a rack to lower-middle of your oven and pre-heat to 325-degrees.
Trim away any excess or hard fat, and cut into 1-1/2″ pieces.
Sprinkle beef cubes with salt and pepper.
Finely chop onions.
Add 3 T vegetable oil in Dutch oven placed over medium-high burner.
Sauté onions for 10 minutes until well-browned.
Add tomato paste and use a garlic press to press the garlic directly into pan. Cook for 2 minutes until the mixture turns rust-colored.
Add ¼ C flour and continue to cook for 1 minute.
Use a whisk to incorporate chicken broth, ½ bottle Guinness (promptly consume the remaining half of bottle one), brown sugar, and minced thyme, then use the liquid to de-glaze the fond.
Bring the mixture up to a simmer, then simmer for 3 minutes. Add beef cubes and bring back up to a simmer.
Put the Dutch oven uncovered, into the pre-heated oven and cook for 2½ hours at 325-degrees stirring after both 45 minutes and 90 minutes (gently stir more like folding).
Wash and peel carrots, and cut into segments.
Wash the potatoes, but leave the potatoes unpeeled; cut them into pieces.
After 2½ hours has elapsed, mix in potatoes and carrots. Continue to cook for 1 more hour, until the beef and vegetables become tender; stirring gently after 30 minutes.
Add ½ bottle Guinness (Hey lookie there... a half a bottle of beer.) and minced parsley.
Adjust salt and pepper according to your taste, and serve.
Recipe by Man of Leisure.info at https://manofleisure.info/guinness-beef-stew/