Gather all ingredients.

Preheat the oven to 350 degrees F (175 degrees C). Lightly grease a 9x13-inch baking dish.

Place potatoes into a large pot and cover with salted water; bring to a boil. Reduce heat to medium-low and simmer until tender, about 20 minutes. Drain and return potatoes to the pot to dry.

Meanwhile, arrange bacon in a large skillet and cook over medium-high heat, turning occasionally, until evenly browned, about 10 minutes.

Drain bacon on a paper towel-lined plate; crumble and set aside.

Combine 1 1/2 cups Cheddar cheese, evaporated milk, 1/2 cup green onions, sour cream, 1/2 of the crumbled bacon, salt, and black pepper in the pot with potatoes. Mash with a potato masher until creamy.

Spread mixture into the prepared baking dish.

Bake in the preheated oven for 25 minutes. Sprinkle with remaining Cheddar cheese, green onions, and bacon. Return to the oven and continue baking until cheese is melted, about 5 minutes more.

Serve hot and enjoy!