Melt butter in a large skillet over medium heat. Add garlic and pepper. Add beef in batches and brown thoroughly.
Put beef into a soup pot with wine, beef base, consomme, onion, celery, parsley, basil, bay leaves and garlic salt. Bring to a boil, lower heat, cover and simmer for 45-60 minutes, until meat is tender.
Add carrots and potatoes; simmer until tender. Add mushrooms and cook a few minutes longer until mushrooms are cooked through. Adjust seasonings, to taste.
To thicken, mix cornstarch with enough water to form a smooth, slightly thick mixture; stir into stew, remove from heat and serve.