Steakhouse Potatoes Romanoff

Ingredients

• Ingredients
• 1 teaspoon butter, or as needed
• 3 large russet potatoes, scrubbed
• ¼ cup minced shallots
• 3 teaspoons kosher salt
• ½ teaspoon freshly ground white pepper
• 1 pinch cayenne pepper, or to taste
• 2 ½ cups grated sharp white Cheddar cheese
• 1 ¾ cups sour cream