Peel and chop Russet and Yukon Gold potatoes into evenly sized chunks. Place in a large saucepan, cover with salted water, bring to a boil, then simmer for 15-20 minutes until fork-tender. Drain and steam dry for a minute.

Return potatoes to the saucepan, add unsalted butter and heavy cream. Cover to melt the butter (2-3 minutes), then mash until smooth.

In a large skillet, melt an additional tablespoon of butter over medium heat. Add chopped onion and sauté for 3-4 minutes until translucent. Add shredded green cabbage, stirring for about 7-8 minutes until tender.

Fold sautéed cabbage and onion mixture into mashed potatoes. Mix gently, then stir in half the crispy bacon and season with salt and pepper.

Transfer to a serving bowl, top with remaining bacon and a few pats of butter. Serve hot.