Peel and quarter potatoes. Cover with water and a dash of salt. Bring to a boil and simmer 25-30 minutes until fork tender.

While potatoes are cooking, heat 4 Tbsps of butter in a large skillet. Add the leeks and cook over medium heat about 10 minutes til leeks are soft. Add the garlic and cook 1 minute. Add the cabbage and cook another 10 minutes or so until cabbage is wilted and soft. Stir often.

When potatoes are cooked drain them and mash roughly. You want them to be quite coarsely mashed. Add the cabbage mixture and stir to evenly incorporate.

Add the milk, cream,remaining butter, salt and pepper and stir thoroughly. Add the parsley last and mix in. Transfer to serving bowl and pass with additional butter if desired.

Optional Fried Leek Topping: Heat vegetable oil in a heavy skillet (cast iron is great). Test it with 1 piece of leek. It should sizzle when the leek hits the oil. Add the leeks when the oil is ready. Cook, stirring until the leeks turn golden brown. This can take about 7 minutes. Stir often and watch so they don't burn. When done transfer leeks to a paper towel to absorb any excess oil. Top the colcannon casserole dish with fried leeks.