In large bowl, beat eggs, add corn and ALL liquid in cans included and the Jiffy mix. Stir together. In small skillet, melt the butter and saute the onions for about 5 minutes. Sprinkle with pepper and a sprinkle of garlic powder while cooking. Add the butter and onion mixture to the other ingredients in the bowl. Stir well. Pour into a 13X9 baking dish and cover. Bake at 350 for 1 hour.