Preheat your oven to 375°F (190°C).

Prepare your vegetables: peel and cut the potatoes into chunks, slice the carrots into coins, dice the onion finely, and shred the cabbage.

Heat a large skillet over medium-high heat, add olive oil, and brown the ground lamb with 1.5 teaspoons of salt for about 7-9 minutes.

In the same skillet, add diced onions and carrot coins, season with salt, and sauté for 6-8 minutes until tender, then add tomato paste and cook for 1 additional minute.

Sprinkle flour over the vegetables and stir for 1 minute. Return the lamb, add Worcestershire sauce, chicken broth, and pepper, and thicken for 1-2 minutes. Fold in peas and parsley before transferring to a greased baking dish.

Bring salted water to a boil, add potato chunks, and cook for 12-15 minutes until fork-tender. Sauté shredded cabbage with olive oil and salt in another pan for 7-9 minutes until tender and lightly browned.

Drain the potatoes, mash until creamy, then mix in sautéed cabbage, whole milk, and butter until well combined.

Spread the colcannon topping over the lamb filling in the baking dish, smoothing it out, and bake for 30-35 minutes until golden and bubbling.

Once baked, let the pie rest for 10 minutes before slicing and serving.