Creamy, cheesy and savory this loaded mashed potato casserole is the perfect side dish.
Bring water to a boil over high heat. Once boiling, reduce the heat to medium-high heat. Cook potatoes for 15-20 minutes or until potatoes are tender.
Preheat the oven to 350 degrees. Lightly spray a 9×13 pan with oil.
Drain potatoes in a colander and set to the side. Place pot back on the stove and melt butter in the pot over medium heat then turn the stovetop off. Add potatoes back to the pot.
Use a potato masher to mash up the potatoes. Add milk, sour cream, and black pepper to the potatoes. Continue to mash and blend the potatoes until smooth with a potato masher.