Preparation Preheat oven to 375°F. Heat oil in heavy large skillet over medium-high heat. Add mushrooms and onion and sauté until mushrooms are brown, about 8 minutes. Using slotted spoon, transfer mushroom mixture to bowl. Add lamb and garlic to same skillet. Sauté over medium-high heat until lamb is no longer pink, about 5 minutes. Return mushroom mixture to skillet. Mix in gravy seasoning and 1 1/2 cups water. Reduce heat and simmer until mixture thickens, stirring occasionally, about 5 minutes. Add peas; simmer until just tender, about 5 minutes longer. Mix in 3 tablespoons parsley; season generously with freshly ground black pepper. Transfer lamb mixture to 13x9x2-inch glass baking dish. Spoon Buttery Mashed Potatoes over, covering completely. Bake pie until heated through, about 15 minutes. Sprinkle with remaining 1 tablespoon parsley.
Preparation Preheat oven to 375°F. Heat oil in heavy large skillet over medium-high heat. Add mushrooms and onion and sauté until mushrooms are brown, about 8 minutes. Using slotted spoon, transfer mushroom mixture to bowl. Add lamb and garlic to same skillet. Sauté over medium-high heat until lamb is no longer pink, about 5 minutes. Return mushroom mixture to skillet. Mix in gravy seasoning and 1 1/2 cups water. Reduce heat and simmer until mixture thickens, stirring occasionally, about 5 minutes. Add peas; simmer until just tender, about 5 minutes longer. Mix in 3 tablespoons parsley; season generously with freshly ground black pepper. Transfer lamb mixture to 13x9x2-inch glass baking dish. Spoon Buttery Mashed Potatoes over, covering completely. Bake pie until heated through, about 15 minutes. Sprinkle with remaining 1 tablespoon parsley.