Preheat oven to 425. Trim excess fat off leg of lamb. Using a knife, make six incisions on top of leg and insert garlic slivers. Repeat on reverse side of lamb leg.
Place leg of lamb on roasting rack in roasting pan. If you have meat thermometer, place it in the heaviest part of the leg. Bake at 425 for 20 minutes, turn oven down to 350. While oven temperature is reducing, take lamb out of oven and baste liberally all over leg with marinade, using a brush. Repeat brushing with marinade every 20 mins. until lamb is done.
1/2 C. light olive oil or corn oil
2 cloves crushed garlic
1 C. lemon juice
1 T. oregano rubbed between fingers to release oils
1 tsp. rosemary
1 tsp. salt
1/2 tsp. freshly ground pepper
Baking time depends on size of leg -- 10 to 12 mins. per pound for pink meat (145 degrees on thermometer); 15 mins. per pound for medium (155 degrees) and 20 mins. per pound for well done (165 degrees).
Take meat out of oven and let rest 10 minutes before carving.
Note: Marinade may be stored in refrigerator -- is also good used on chicken.