Boil potatoes in salted water for 20 minutes (or until fork tender).
Meanwhile, wash and trim kale, discarding the spines of the leaves. Blanch, drain, gently squeeze out the water and chop finely. Set aside.
Heat2 tablespoons butter and garlic powder in a large frying pan and cook leeks until tender over low heat, about 5-10 minutes.
Add the chopped kale and 2 Tablespoons butter and cook an additional 10 minutes,stirring frequently.
Season with pepper to taste.
Drain and mash the potatoes.
Whip in the kale mixture and 1 teaspoon salt.
Slowly beat in cream until mixture is smooth, but still firm.
Season with additional salt & pepper if needed.
In a small frying pan, brown the onions in the remaining butter.
Create a mound of the potatoes in a serving dish.
Make a depression in the center and pour the browned onions and butter in the well until they spill over the side.
Sprinkle with chopped parsley. (the photo shows a version I make without the onion topping.)