Preheat oven to 350°F. Heat oil in a heavy nonstick skillet over medium high heat. Cook chops 1 minute per side or until browned. Arrange chops in a casserole dish. Combine next 4 ingredients in a bowl and pour over chops. Cover and bake 25 minutes per pound. Sauté mushrooms in same skillet over medium heat, stirring, 4-5 minutes until brown. Transfer mushrooms to a bowl. Sauté onions 5 minutes, stirring until golden. Combine cooked onion with mushrooms and stir through lamb casserole. Bake , uncovered, another 20 minutes, or until top is browned.
