Preheat oven to 350 °F.
Melt the butter on the stove or in the microwave and pour it into a baking pan. Use a brush to spread it evenly all over the baking dish.
Crack the eggs into a separate bowl. Whisk them well and add some salt to the eggs if you like.
Start pouring milk into the whisked eggs gradually. Keep on whisking. Once everything is combined well, the mixture is ready to be poured into your buttered baking pan.
Place this baking dish with the eggs into the oven. Bake it for 9 minutes.
Then stir the eggs and bake them again for 10 minutes.
Remove from oven and serve.