In a mixing bowl, combine butter, egg whites, and cream cheese. Whisk until smooth.
Stir in onion, bell pepper, whole kernel corn, and creamed corn. Mix well.
In separate medium sized bowl, stir the dry ingredients (flour, cornmeal, sugar, baking powder, and salt) together. Mix well.
Add mixed dry ingredients to large bowl with corn and vegetable mixture. Season with black pepper. Mix, stirring until well combined.
Pour mixture into prepared dish. Bake approximately 50 mintues, or until golden around edges and set in center. Insert a toothpick to test doneness. When fully cooked through, it will come out clean.
During our Thanksgiving prep, my mom (Mimi) and I always debate if we should double this recipe. We typically make one recipe and we have plenty. But it depends on the size of your group and how much leftover Corn Fritter Casserole you want to consume.
Gluten-free option: substitute gluten-free for gluten-full flour.
If your casserole is browning too fast during the cook time, cover loosely with foil.