Lemon-herb Lamb Roast

3 lb Boneless center-cut leg of Lamb
1/2 tsp Finely shredded lemon peel
1 tbsp Lemon juice
1/2 tsp Dried rosemary
1/4 tsp Dried crushed thyme
1/4 tsp Pepper
3 cup Plain yogurt
1 tbsp Cornstarch
3/4 tsp Beef bouillon granules

Trim fat from lamb; cut four evenly spaced 1" deep slits in the surface. Combine lemon peel, juice, rosemary, thyme and pepper; rub onto meat and into slits. Place meat on the rack of a roasting pan. Insert a meat thermometer into the thickest portion. Roast in 325° F oven for 1 1/2 to 1 3/4 hours or until the thermometer registers 150 degrees 150 degrees F (medium). For sauce, reserve pan juices; skim fat. Add water, if necessary, to measure 2/3rds cup liquid total. In a medium saucepan stir together yogurt, cornstarch and bouillon granules. Stir in juice mixture. Cook and stir until thickened and bubbly.

Cook and serve with sliced meat.