Butter 8-inch square pan. Drain liquid from salmon; add enough milk to liquid to measure 3/4 cup. Flake and bone salmon. Combine egg, lemon juice, onion,salt and pepper, salmon and milk mixture, and blend well. Add sour cream and mayonnaise and dill to taste. Spoon into baking pan. Bake at 350 degrees for 1 hour. Makes 4 servings.