Boil potatoes for 15 minutes and drain. Cook and chop your bacon.
Preheat oven to 350F, and mash with sour cream, minced onion, salt, and pepper. If you normally add butter and/or milk to your mashed potatoes, you may do so but I typically don't with the cheese and sour cream included.
Separate 1 c. cheddar and stir it into mashed potatoes. Reserve 1 c. for topping.
Spoon potatoes into a 9x13 glass pan. Top with bacon and remaining 1 c. of cheese.
Bake uncovered for 20-30 minutes, until heated through and cheese melts. Do not allow cheese to brown.
Recipe by Happy Hour Projects at https://happyhourprojects.com/twice-baked-potato-casserole/