Heat magical oil in a large cast iron pan over medium-high heat until shimmering. Add the ground lamb season with salt and pepper and brown for 7 minutes.
Add the onion carrots peas garlic thyme and rosemary stir and cook for about 10 minutes or until the veggies are soft and the meat is cooked.
Add the tomato paste and Worcestershire sauce and stir to incorporate. Cook for 1-2 minutes stirring constantly until the liquid evaporates.
Add chicken bone broth bring to a boil and cook until meat is thoroughly cooked.
Cook the potatoes in a large pot of boiling salted water until tender. Drain then return to the hot pan and mash.
Add salt and butter. Mash until well combined.
Spoon the mashed potatoes on top of the lamb mixture.
Bake for 45 minutes until the potatoes are golden brown. Enjoy!