Beat eggs, sour cream, milk and salt. Stir in onions.
Additions - cubed ham, sausage, Cheddar cheese. If you add any of these, omit the salt.
Melt butter in 9 x 13 pan in the oven. Remove pan from oven. Tilt pan to spread butter. Pour ingredients into pan and return to oven. Bake 325° for 35 minutes or until center is set.