Preheat oven to 240°C (220°C fan-forced). Lightly spray a roasting pan with oil. Combine 1 tbsp oil, mustard and garlic in a small bowl. Season.
Place beef in pan and rub top side of beef with mustard mixture. Place beef in oven and reduce heat immediately to 200°C (180°C fan-forced). Roast for 45-60 minutes (for medium-rare to medium), or until cooked to your liking, covering top of roast with foil if over-browning. Remove from oven, cover loosely with foil and rest for 10 minutes.
Arrange vegetables in separate large baking tray lined with baking paper. Drizzle with remaining oil, season and roast with beef for 1 hour until golden and crisp.
Thinly slice beef and serve with roasted vegetables, steamed greens, gravy and extra tarragon, if desired.
Blade roast, sirloin or scotch fillet roast would also work well.
Test roast for doneness using a meat thermometer - test in the centre of the beef, 60°C for medium rare.
Resting the meat will ensure it remains tender and moist when carving.