1.Preheat oven to 200°C (180°C fan-forced).
2.Brush beef with half the oil; season. Heat remaining oil in large frying pan; cook beef, over high heat until browned all over. Transfer beef to medium shallow baking dish; roast about 45 minutes or until cooked as desired. Cover with foil; stand 20 minutes, then slice beef thinly.
3.Meanwhile, melt butter in same frying pan; cook onion, carrot, celery, garlic, rosemary and bay leaves, stirring, until onion softens. Add paste and flour; cook, stirring, until mixture is browned. Gradually stir in stock, wine and the water; bring to the boil. Reduce heat; simmer, uncovered about 10 minutes or until gravy thickens. Strain gravy into medium heatproof jug.
4.Spread softened butter over roll halves; sandwich with beef slices and gravy.