Coat beef pieces in flour, shake off any excess flour. Transfer to pot and brown on all sides. About 4 min. Remove beef from pot and set aside.
Add onion and mushrooms. Cook until onions are tender. About 3-5 min depending on size of onion.
Add garlic, stir and cook until fragrant. About 1-2 min.
Transfer beef back into pot. Add broth, crushed tomatoes, beer, tomato paste, salt, pepper and thyme. Bring to boil. Reduce heat and simmer for 1 hour.
Add carrots and potatoes, return to boil. Reduce heat and simmer until veggies are tender. About 1 hour.
Stir together cornstarch and cold water in a small bowl. Pour into pot and stir in along with balsamic vinegar. Simmer until thick and bubbly. About 4 min.