1. In a large saucepan, cook onion and garlic in olive oil for 5 minutes until softened and turning golden.
2. Tip in the beef strips, pepper, tomatoes and rosemary, then bring it to boil.
3. Simmer for 15 minutes until the meat is cooked through, adding some boiling water if needed.
4. Stir through the olives and serve with mash or polenta.