In a large pot place potatoes, chicken stock and enough water to cover. Bring to a boil, reduce heat, cover and simmer for 25 minutes until fork tender.
Place bacon in a large, deep skillet over medium heat. Cook stirring often until crisp. Remove bacon from the pan, and drain on paper towel. Place cabbage in pan with the bacon drippings over medium heat. Cook 5-6 minutes until tender. Season to taste with salt and pepper.
While the cabbage cooks, place cream and leeks in a saucepan and simmer until softened, about 20 minutes.
Drain the cooked potatoes and return to pot. Pour in warm leek/cream mixture. Stir in cooked cabbage and bacon. Season to taste with salt and pepper.
Place colcannon in a serving dish, pour melted butter over top and sprinkle with chopped parsley. Serve immediately or keep warm in the oven.