Place the potatoes in a large saucepan and cover with water. Season with salt. Bring to a boil and cook for about 20 minutes, or until tender. Drain well and transfer to a large bowl.

While the potatoes cook, heat a Dutch oven over medium heat. Add the diced bacon and cook until crispy. Remove bacon with a slotted spoon and drain on a paper towel-lined plate.

Drain most of the bacon fat, leaving about 2 tablespoons in the pot. Add leeks and scallions, sautéing until softened (about 5 minutes).

Add the chopped kale and cook for 2-3 minutes, until wilted.

Mash the drained potatoes with 3 tablespoons of butter. Stir in the sautéed greens and continue mashing until smooth.

Mix in the heavy cream and bacon. Season with salt and black pepper to taste.

Top with the remaining butter and some chopped scallions. Serve warm!