Preheat the oven to 375°F (190°C)
Pat the lamb roast dry with paper towels
Season all sides with salt and black pepper
Rub with olive oil
Add minced garlic, rosemary, and thyme
Place sliced onions and carrots in a roasting pan
Set the lamb roast on top of the vegetables
Insert a meat thermometer into the thickest part of the roast
Roast until the internal temperature reaches your preferred doneness
Remove from the oven and let rest for 15 to 20 minutes
Slice against the grain
Serve warm