Preheat the oven to 350°F and spray a 3 quart baking dish with cooking spray.
On the stove top over medium-high heat, cook diced onion and carrot in a couple of drizzles of olive oil. Cook for about 5 minutes or until carrots are tender and onion is beginning to brown. Add seasoned salt, pepper and minced garlic. Cook for 1 minute.
Add the ground lamb cooking until no pink remains. Adjust the seasoned salt and black pepper, to your taste. Drain excess fat from the pan.
Add Worcestershire, beef broth, tomato paste, fresh thyme, Mrs Dash and frozen baby peas. Stir over low heat just until thickened around 1-2 minutes. Remove from the stovetop adding chopped parsley.
Pour into the baking dish and spread the mashed potatoes on top. Brush the top of the potatoes with melted butter.
Bake for 30-35 minutes until the top is golden and the edges are bubbly. Increase the oven to broil, if needed to brown the top.