In a large soup pot or Dutch oven over medium heat, cook meat until crisp, about 12–13 minutes. Transfer to paper towels. Return pot with 3 tablespoons of the fat; add butter if needed to total 3 tablespoons. For vegetarian version, melt butter instead.

Over medium-low heat, sauté the white parts of scallions and garlic until golden, 2–3 minutes, stirring frequently.

Add potatoes, milk, and 2 teaspoons salt. Bring to a boil over medium-high heat carefully to avoid curdling. Once boiling, reduce heat, cover, and simmer until potatoes are tender, 10–15 minutes.

Meanwhile, prepare potato skins: heat olive oil in a skillet over medium-high heat. Add potato peels in a single layer and cook until crisp and golden, about 3 minutes, flipping once. Drain on paper towels. Sprinkle with salt, pepper, cayenne, and garlic powder. Crumble and set aside.

When potatoes are tender, remove pot from heat. Purée soup with an immersion blender for smooth texture or mash for chunkier soup.

Stir in sour cream and cheese until combined. Season with salt and pepper to taste.

Serve topped with crumbled meat, extra sour cream, cheese, green scallion parts, and crumbled potato skins.