1.Preheat oven to 200°C/180°C fan-forced.
2.Rub beef with 2 teaspoons of the oil; sprinkle with salt and freshly ground black pepper. Heat 1 tablespoon of the oil in flameproof baking dish; cook beef until browned all over. Add onions to dish; roast, uncovered, in oven 20 minutes.
3.Place zucchini, tomato, eggplant and capsicum around beef in dish; roast further 40 minutes or until beef is cooked as desired. Remove beef from dish, cover with foil; stand 10 minutes.
4.Increase oven temperature to 240°C/220°C fan-forced; roast vegetables further 10 minutes or until browned and tender. Drizzle vegetables with combined remaining oil, vinegar, herbs and capers.
5.Serve thinly sliced beef with vegetable mixture.