Step 1. Preheat oven to 200°C. Line a large baking tray with baking paper. Whisk oil, vinegar and pepper in a bowl. Add lamb and turn to coat.
Step 2. Place pumpkin and onion on baking tray. Drizzle with oil. Roast, turning once, for 35 minutes or until golden and tender. Add asparagus to roasting tray for final 5 minutes.
Step 3. Meanwhile, preheat a barbecue grill on medium-high heat. Barbecue lamb for 3 to 4 minutes on each side for medium or until cooked to your liking. Transfer to a plate. Cover with foil. Stand for 5 minutes. Thinly slice.
Step 4. Place rocket and feta in a large serving bowl and add pumpkin, onion and asparagus. Toss gently to combine. Place salad on serving plates. Top with lamb and serve.