Potatoes Romanoff

5 cups cooked, cold diced potatoes
2 teaspoons salt
Garlic powder, to taste
1/2 cup chopped scallions, including tops
1 (8 ounce) container sour cream
1 (16 ounce) container large-curd cottage cheese
1/2 cup shredded sharp Cheddar cheese
Paprika

Mix first 6 ingredients and place in a greased casserole dish. Top with cheese. Dust heavily with paprika. Bake at 350 degrees F for 30 minutes.