Stir together first 8 ingredients until thoroughly blended. Pour into a greased 13- x 9-inch baking dish; dot with butter, and sprinkle evenly with nutmeg. Place dish in a large baking pan; add hot water to a depth of 1 inch.
Bake at 350° for 1 hour or until lightly browned and set. Cool slightly, and cut into squares. Serve with Lemon Sauce, if desired.