Peel and chunk the large Russet and Yukon Gold potatoes. Place them in a large saucepan, cover with salted water, and bring to a boil over medium-high heat. Cook for 15-20 minutes until fork-tender. Drain and let sit briefly.

Melt 2 tablespoons of unsalted butter in a large skillet over medium heat. Add chopped medium onion and sauté for about 5-7 minutes until tender and translucent. Stir in chopped green cabbage and cook for another 7-8 minutes.

In a large mixing bowl, combine the drained potatoes with the sautéed onions and cabbage. Add in 1/2 cup of heavy cream and 2 tablespoons of unsalted butter. Mash until smooth and creamy, adjusting seasoning with kosher salt and fresh pepper.

Gently fold in half of the crispy cooked bacon into the potato mixture, ensuring even distribution without over-mixing.

Transfer the mixture to a serving bowl, topping with remaining crispy bacon and a few pats of butter. Serve warm.