Preheat oven to 375°F; lightly oil an 8-by-8-inch baking dish. Use fully cooked rice or pasta and cooked vegetables.
Whisk milk, beaten eggs, salt and pepper in a bowl; fold in cooked grains, vegetables and half the cheese.
Stir in special additions (cooked chopped green beans, garlic powder) and spoon mixture into the baking dish. Sprinkle remaining cheese on top.
Bake uncovered 30–35 minutes until the center is fully set and an instant-read thermometer registers at least 165°F.
Rest 10 minutes before serving.