hot mustard dressing
Preheat oven to 200ºC (390ºF). To make the hot mustard dressing, combine mustard, vinegar, oil and sugar in a bowl. Set aside.
Place tomato, onion, 2 tablespoons of oil, salt and pepper on a baking tray and toss to coat. Roast for 30 minutes. Set aside. Heat a char-grill pan or barbecue over medium heat. Brush the beef with remaining oil, sprinkle with salt and pepper and cook for 5–6 minutes each side or until cooked to your liking. Slice, toss with tomatoes, rocket and dressing to serve.