Gather the ingredients. Preheat the oven to 375 degrees F (190 degrees C). Lightly grease a 9x13-inch baking dish.
Heat a large, deep skillet over medium-high heat. Cook sausage in the hot skillet until evenly browned and crumbly, 5 to 7 minutes. Drain and discard grease.
Stir together shredded potatoes and butter in the prepared baking dish; lightly press mixture into the bottom and sides of the dish.
Mix together sausage, cottage cheese, Cheddar cheese, onion, and eggs in a bowl. Pour over potato mixture.
Bake in the preheated oven until a toothpick inserted into the center of casserole comes out clean, about 1 hour. Let cool for 5 minutes before serving.
Enjoy!
