Take the rack out for 1 hour before putting it in the oven. Have the plastic wrap still intact while it rests to room temperature.
Preheat oven to 375°F. Take the top rack out of the oven, and place a rack at the bottom third.
One the lamb has rested for 1 hour on the countertop, take out a roasting pan with a rack. Unwrap the plastic around the lamb, and place the rack with the exposed bones up on the oven and the neatest part of the lamb sitting on the roasting pan.
Bake the rack of lamb for 25 minutes. Or to know if the lamb is ready, insert a thermometer into the center or thickest part of the meat. The temperature should read 125°F for rare or 135°F for medium rare.
While the lamb is roasting, make the mango mint sauce. Using a food processor, add the mint, parsley, lemon juice, and garlic. Pulse the liquid about 15 times. If you like it smoother, turn it on and process continuously for 15 seconds. Scrap the sauce out and stir in the mango chunks, salt, and pepper. Set aside.
Take the lamb out and let it rest for 15-30 minutes before carving into the meat. Serve the mango mint sauce on top or on the side.
optional: place small aluminum strips on to the exposed bone on the rack. This allow the bone to not burn and protect the bone from high heat. It is for the purpose of aesthetic.