An hour before you start roasting the lamb, line a large, rimmed baking sheet with foil and spray it with olive oil spray.
Place the lamb on the prepared baking sheet, fat side up. Score the fat by making small shallow slits 1 inch apart.
Liberally spray both sides of the lamb with olive oil and sprinkle it with salt, pepper, garlic powder, rosemary, and thyme. Allow the lamb to rest on the counter for about an hour and come to room temperature.
Preheat your oven to 425°F.
Roast the lamb in the preheated oven until an instant-read thermometer inserted into the thickest part (not touching the bone) reads 135°F (medium-rare), about 25 minutes.
Remove the lamb from the oven. Transfer it to a cutting board. Cover it with foil, and let it rest for 10 minutes.
To cut the rack into individual ribs, turn it upside down, locate where the bones are, and carefully cut between them using a sharp chef's knife.
Serve immediately.
Video
Notes
The USDA says we should cook roasts to an internal temperature of 145ºF with a three-minute rest time.
A small, 1-pound rack (like the one shown in the process shots and video) will need about 20 minutes in the oven to reach medium-rare doneness.
You can keep the leftovers in the fridge, in an airtight container, for 3-4 days. Reheat them gently, covered, in the microwave at 50% power to avoid drying them out.