Heat olive oil in a large pot over medium heat.
Add the beef and brown it on all sides.
Remove beef and set aside.
Sauté the onion and garlic until translucent.
Add the diced potatoes and mixed vegetables; stir for a few minutes.
Return the beef to the pot.
Pour in the beef broth and diced tomatoes.
Season with thyme, salt, and pepper.
Bring to a boil, then reduce heat and simmer for 45 minutes.
Taste and adjust seasoning if necessary.