1. Preheat oven to 350F. Peel and chop potatoes into 2 inch chunks. Peel and dice onion and carrots.
2. In a large saucepan, cover potatoes with salted water and boil until tender.
3. Drain and transfer to a bowl with 2/3 of the coconut oil. Use a potato masher or hand mixer to mash until smooth. Season with sea salt and pepper to taste and set aside.
4. Meanwhile, heat the beef broth in a small saucepan until hot.
5. Sauté onions and carrots with remaining oil until they begin to soften. Add the ground lamb to brown, breaking apart into small pieces with a wooden spoon.
6. If there is an excess of oil after the meat is browned, carefully pour it off and discard so that the final gravy consistency is correct.
7. Sprinkle in flour, then slowly stir in the hot beef broth and cook until the liquid thickens into a gravy.
8. Add the peas and season with salt and pepper to taste.
9. Transfer the meat mixture into a shallow 2-quart casserole dish. Spoon the mashed potatoes over the meat and spread evenly.
10. If you'd like to freeze the pie, do so now by covering the dish with a layer of parchment paper, tightly covering with foil, and placing in the freezer.
11. If cooking now, bake uncovered for 30 minutes, or until the top is lightly browned.
12. To cook from frozen, remove from the freezer and allow to defrost on the counter for 1 hour.
13. Remove foil and parchment, and place in a cold oven. Set the temperature to 350F and allow to bake for 45-60 minutes or until hot through the center and lightly browned.