Chef John's Colcannon

Boil potatoes in a large pot of salted water until tender about 10 minutes. Drain and transfer potatoes to a large bowl. Add 2 tablespoons butter and lightly mash the potatoes.

Boil kale and leeks in a large pot of water until tender 5 to 7 minutes. Drain and transfer kale and leeks to a blender. Add white parts of the green onions and 2 more tablespoons butter; blend until smooth scraping down sides as needed 1 to 3 minutes.

Stir pureed kale mixture into the bowl of potatoes and continue to mash. Season with salt and black pepper to taste. Add cream and stir until desired texture. Top with 2 tablespoons butter and green parts of the green onions.