Preheat oven to 350°F. Grease 9×13-inch glass baking dish. Cook bacon and onion in heavy large skillet over medium heat until bacon is crisp and onion is translucent, stirring frequently, about 8 minutes. Transfer to paper towel using slotted spoon. Drain well. Combine eggs with next 3 ingredients. Mix in bacon mixture. Pour into prepared baking dish, spreading mixture evenly. Bake until center is set, about 45 minutes. Cut into squares and serve.