Preheat oven to 350 degrees F. Coat four mini casserole dishes with non-stick cooking spray, and set aside.
In a large bowl, mash the potatoes with a potato masher. You can leave the skins on like I do of peel the potatoes.
Mix 3/4 cup cheddar cheese, sour cream, milk, butter, green onions, salt, and pepper into the mashed potatoes.
Spoon potato mixture evenly among the four prepared mini casserole dishes. Divide 3/4 cup cheddar cheese and crumbled bacon among the four dishes, sprinkling first the cheese then the bacon over the top each mini casserole.
Bake in the preheated oven until just bubbling, about 10 to 15 minutes. Cool for at least 5 minutes before serving. Garnish with more green onion if desired.