Combine the garlic, seasoning, and oil together and mix. Spread the mixture evenly on the rack including the back and sides.
Place lamb and let marinate for 2 hours or overnight. Be sure to take lamb out of fridge 30 minutes to an hour before you cook it.
Heat oil in a cast iron skillet. Place the rack of lamb fat side down in the skillet and cook for 3 minutes. Flip the rack over and cook for another 3 minutes before transferring to a 450° oven for 30 minutes.
Let rest for 10-15 minutes before slicing.