NOTE: food.com did not recognize "frozen latkes" as an ingredient, so I used "frozen hash brown potatoes" instead. These are an acceptable substitute, but frozen latkes are preferred.
Heat frozen latkes in oven per package directions to the point where they are reheated, but not yet fully crispy, usually about 1/2 to 2/3 of the package direction cooking time, or about 10 minutes in a 425 degree Fahrenheit oven. Set aside to cool. When cooled to room temperature, shred the latkes by hand.
Preheat oven to 350 degrees Fahrenheit. Oil or spray a 13x9-inch (3-quart) baking dish with cooking spray.
Heat 1 tablespoon butter in a skillet, add chopped onion, and sauté over medium-low heat for about 7 minutes until soft but not brown. Add garlic and cook another minute.
In a separate bowl, combine cooked onion, garlic, chives, sour cream, cottage cheese, Cheddar cheese, Swiss cheese, eggs, pepper, mustard powder, and 1 teaspoon of the salt.
Reserve approximately 3/4 cup of the shredded latkes for crust. Fold the rest of the shredded latkes into the onion-cheese mixture and combine by hand.
Pour mixture into baking dish and spread evenly.
Melt the remaining 3 tablespoons of butter and add the remaining 1 teaspoon salt, paprika, and Parmesan cheese. Add the remaining shredded latkes and combine by hand.
Spread the latke-Parmesan mixture evenly over the top of the mixture in the baking dish.
Bake about 1 hour or until set with a golden brown crust.