In a medium sized bowl whisk together the eggs, milk, flour, sugar and salt till smooth. Set aside until the oven is preheated and the pan is hot. Add the two tablespoons of butter to the cast iron skillet(or pie plate or whatever you're using) without removing it from the oven. Close the oven door and check on the butter every minute and when it's completely melted remove the pan from the oven. Swirl the butter around so that it covers the bottom of the pan, then pour the batter in. Immediately place it back in the oven and bake for 35-45 minutes until puffed and golden brown. Remove and cool for a few minutes. It will deflate as it cools. After a few minutes, cut and serve with a light dusting of powdered sugar and a squeeze of lemon, pure maple syrup, your favorite fresh fruits or your favorite preserves or fruit compote.