Open salmon, remove bones and mash (don't discard skin or liquid). Flake salmon and add bones and next 3 ingredients. Beat together 1 cup milk, the eggs, onion, and seasoned salt and pepper to taste.
Add to salmon mixture with lemon juice. Put in greased 1 1/2 quart casserole and set casserole in flat baking dish containing 1 inch hot water. Bake in preheated 350 degree oven 1 hour.