Preheat oven to 350 degrees. Grease a 4 quart glass baking dish.
Bring broth, salt, pepper and garlic powder to a boil in a 2 quart sauce pan. Stir in grits until completely combined. Reduce heat to low and cook for 8 to 10 minutes until grits are thick. Add the cubed cheddar and milk and stir to combine. Gradually stir in the eggs and butter until combined.
Pour mixture into prepared casserole dish. Sprinkle with shredded white cheddar cheese. Bake for 35-40 minutes or until set.