To make things more convenient, Steps #1 - #4 can be done a day in advance, and then cover the dish and store in refrigerator until you're ready to bake and serve it (though it might require a few extra minutes of baking time).
1Preheat oven to 350°F. Spray a 13x9-inch (3-quart) glass baking dish with cooking spray; set aside.
2Steam or cook corn as directed on bag.
3Meanwhile, in 12-inch skillet, melt butter over medium-high heat. Stir in bell pepper, poblano chile, and onion; cook 3 to 5 minutes, stirring frequently, until crisp-tender. Stir in corn. Remove from heat.
4In a large bowl, beat eggs, sour cream, cornmeal, sugar and salt with wire whisk until well blended. Stir in corn mixture and cheese. Pour into prepared baking dish.
5Bake 20 minutes. Sprinkle the top with French-fried onions, and return baking to oven, and bake about 10 minutes longer or until knife inserted in center comes out clean. Cool 5 minutes before serving.