Preheat oven to 400 degrees.
Place the butter in a 9x13-inch baking pan, then put the pan in the oven while the oven is preheating to melt the butter.
In a large bowl, mix the remaining ingredients together (eggs, flour, milk, and salt).
Pour egg mixture into the melted butter (watch for hot splatters).
Return the pan to the oven and bake for 15-20 minutes.
Let cool slightly.
Cut the pancake into squares and serve with maple syrup or sliced bananas and powdered sugar.