Store lamb tenderloins in your freezer until you're ready to use them, then thaw only as many as you need.
For thawing tips, please read Safely Defrosting Frozen Food for Maximum Flavor.
In addition to roasting lamb tenderloins whole, you can also cut them into medallions (up to 1 inch) or petite fillets (up to 2 inches). Pan sear, sauté, grill, broil, roast, or stir fry the medallions and petite fillets.
If you're planning on roasting them whole, try stuffing them and roasting to medium-rare or medium.
Recommended Cooking Temps:
Rare - 135°
Medium Rare - 140°-150°
Medium - 140°-145°
Medium Well - 160°
Well Done - 165° and above