Season the beef with salt and pepper. Heat oil in a heavy pot over medium-high heat. Brown the beef in batches until nicely caramelized. Don’t crowd the pan—brown, not steam. Set aside.
In the same pot, sauté the onion and garlic until they’re soft and a little golden. If the pan looks dry, add a splash of broth to lift the fond.
Stir in tomato paste and cook for a minute to wake up the flavor. Add thyme and bay leaf.
Return the beef to the pot. Add carrots, potatoes, beef broth, and water. Bring to a boil, then reduce heat to a gentle simmer.
Cover and simmer 1.5 to 2 hours, or until beef is tender and vegetables are cooked through. Stir occasionally and adjust salt/pepper.
If you want a thicker stew, whisk a little cornstarch or flour with cold water and stir in to reach your desired consistency. Simmer a few more minutes to thicken.
Remove bay leaf. Taste and adjust seasoning. Garnish with parsley if you’re feeling fancy.