Start by marinating the cubed beef in a mixture of red wine (if using), garlic, thyme, salt, and pepper. Let it marinate for at least 30 minutes to enhance the flavors.
In your Dutch oven or heavy pot, heat the vegetable oil over medium-high heat. Add the marinated beef and brown it on all sides. This step enhances the flavor of the stew.
Add the chopped onions and cook until they become translucent.
Stir in the carrots, potatoes, and diced tomatoes. Mix well.
Pour in the beef broth, add the bay leaves, and bring the mixture to a boil.
Once boiling, reduce the heat to low, cover the pot, and let the stew simmer for 2.5 to 3 hours, or until the meat becomes tender and the flavors meld together.
Season with additional salt and pepper to taste.