Preheat oven to 400º. Spray a 2-quart baking dish with nonstick cooking spray.
In a large pot, bring 6 cups water to a boil over high heat. Gradually add grits, whisking into water. Reduce to simmer. Cook, uncovered, for 25 minutes or until fully cooked.
In a large nonstick skillet, heat olive oil over medium-high heat. Add onion, and cook for 6 minutes or until lightly charred, stirring often.
Add onion, butter, 1 cup Parmesan, salt, and pepper to cooked grits, stirring well. Let cool for 20 minutes.
Add eggs, stirring well. Spoon into prepared dish. Sprinkle with remaining ¼ cup Parmesan. Bake for 40 to 50 minutes or until fully cooked and golden. Let cool for 5 minutes before serving.
Recipe by Southern Lady Magazine at https://southernladymagazine.com/parmesan-vidalia-grits-bake-recipe/