1) Preheat oven to 375 degrees F. Peel potatoes and grate them into a bowl of cold water. Rinse grated potatoes well to remove starch. Drain and pour out onto paper towels to dry a bit.
2) In a large bowl, stir together sour cream, cheddar cheese, salt, and pepper. Then mix in grated potatoes. Mix together well using your hands if necessary.
3) Spread potato mixture out in a 9×13 baking dish (buttered lightly). Drizzle potato casserole with melted Land O Lakes® Butter.
4) Bake potato casserole at 375 degrees F. for 75-90 minutes until potatoes are very crispy around the edges and tender in the middle.
5) For sausage gravy, cook sausage in a medium pot or skillet over medium heat, breaking up the sausage in the pot as it browns.
6) When sausage is well browned, stir in flour and cook for a minute. Then slowly add in milk, stirring constantly to avoid lumps. You’ll need at least 2 cups of milk, but might need up to 3 to get a nice consistency of gravy. It should be thick, but pourable. Season gravy with salt and pepper.
7) When potato casserole is done, cut it into serving pieces and serve with sausage gravy. Garnish with fresh chives or just dig in!