Heat olive oil in a large pot over medium heat and cook the minced onion until it becomes translucent, about 2 to 3 minutes.
Add the pancetta, fresh rosemary stems, and minced garlic, then sauté everything together for another 2 to 3 minutes.
Coat the beef chunks with 3 to 4 tablespoons of flour, then add them to the pot and simmer on low heat, turning often to brown the meat evenly, for about 5 to 8 minutes.
Stir in the potatoes, tomato paste, oregano, and pepper or hot pepper flakes, then pour in the vegetable broth or water with a bouillon cube.
Cover the pot and let the stew cook gently on low heat for around one hour, until the potatoes are soft and the sauce has thickened.
Check the stew before serving and add salt only if needed, as the broth or bouillon may already contain salt.
Serve hot and enjoy this comforting Italian classic.