Cut potatoes into quarters. Place in a large pot and cover with water.
Bring to a boil and cook until fork tender, about 15 minutes. Drain well.
Cook bacon in a large frying pan until crisp. Remove the bacon but leave the fat.
Heat the bacon fat over medium heat. Lightly smash the potatoes and add to the hot fat. Cook without stirring until golden brown and crispy, about 7-8 minutes. Flip potatos and crisp the other side.
Sprinkle the grated cheese over the smashed potatoes until evenly coated. Season with salt and pepper to taste.
Garnish with sour cream and green onions as desired.