1. Preheat broiler to high.
2. Microwave potatoes according to package directions; stir in milk, butter, and 1/4 teaspoon salt.
3. While potatoes cook, heat a Dutch oven over medium-high heat. Add oil to pan; swirl to coat. Sprinkle lamb evenly with remaining 1/2 teaspoon salt and pepper. Add lamb to pan; sauté 4 minutes, turning to brown on all sides. Remove lamb from pan with a slotted spoon. Add onion to pan, and sauté for 4 minutes, stirring occasionally.
4. While onion cooks, microwave carrots at HIGH for 1 1/2 minutes. Remove carrots from bag; slice diagonally into 1/2-inch pieces. Stir tomato paste into onions in pan; cook 1 minute, stirring frequently. Add wine; cook 2 minutes or until liquid almost evaporates, scraping pan to loosen browned bits. Add flour; cook 1 minute, stirring constantly. Gradually add broth, stirring constantly. Stir in sliced carrots, peas, and herbs. Bring to a boil; cook 4 minutes or until slightly thick, stirring occasionally. Remove from heat; stir in browned lamb.
5. Spoon lamb mixture into a 2-quart broiler-safe ceramic casserole dish; top with mashed potato mixture. Broil 4 minutes or until lightly browned on top.
MyRecipes is working with Let's Move!, the Partnership for a Healthier America, and USDA's MyPlate to give anyone looking for healthier options access to a trove of recipes that will help them create healthy, tasty plates. For more information about creating a healthy plate, visit www.choosemyplate.gov.