Preheat your oven to 400°F (200°C). Wash the red potatoes thoroughly, then arrange them on a baking sheet. Bake for about 45–60 minutes, or until fork-tender. Cool slightly before chopping into cubes.

In a skillet over medium heat, cook the bacon until crispy, about 8–10 minutes. Transfer to paper towels to drain and crumble it.

In a large bowl, combine cubed potatoes, sour cream, crumbled bacon, mozzarella, cheddar, salt, and black pepper. Fold together gently.

Transfer the mixture into a greased 9x13 inch baking dish and spread evenly.

Sprinkle finely chopped green onions over the top. Preheat oven to 350°F (175°C) and bake for about 20 minutes until cheese is bubbly and golden.

Let it cool for 5-10 minutes before serving warm as a side dish.