In a large non-stick sauté pan, cook the ground lamb until no longer pink.
Drain the fat from the lamb and set aside in a clean bowl.
In the same pan, melt two tablespoons butter. Whisk in the flour and allow to cook for a couple of minutes, until starting to brown.
Whisk in the wine and allow to simmer for about a minute.
Stir in the crushed tomatoes and seasonings - Worcestershire sauce, onion flakes, Herbs de Provence, garlic powder, salt and pepper. Bring the mixture to a gentle simmer.
Stir in the peas and carrots and cooked ground lamb. Allow to simmer for a few minutes. Then transfer the lamb filling to a 9x13 casserole dish.
While you are making the filling, preheat the oven to 375 degrees F.
Peel the potatoes and cut into 1 1/2 inch size pieces. Cover the potatoes with cold water.
Bring the potatoes to a boil, then reduce the heat to simmer. Cook the potatoes until fork tender.
Drain the potatoes and return them to the cooking pot.
Add in the 12 tablespoons of butter and half and half. Mash the potatoes until smooth.
Stir in the parsley and Parmesan cheese until well combined. Season with salt.
Top the lamb filling with the mashed potato mixture.
Dot the top of the Shepherd's Pie with a little more butter. Bake for 35-40 minutes until the potato crust is starting to brown and the filling is bubbling.