3 ingredients; gradually stir into egg mixture. set aside. melt butter in a large skillet over medium heat; add onions. cook, stirring often, 30 to 40 minutes or until caramel colored. remove from heat. stir onions into egg mixture; then spoon into a lightly greased 13- x 9-inch baking dish. bake at 350° for 30 minutes or until pudding is set. makes 8 servings. 