First, melt your butter in the microwave or on the stove top. Next, combine eggs, milk, flour and salt in a large mixing bowl whisking until smooth. Spray the insides of 2 9x13 baking dishes with a non-stick spreay or grease well. Finally, pour the melted butter half into each baking dish. Then pour the batter half at a time into each baking dish. Bake at 400 for 18-20 minutes or until puffy and golden brown edges. Serve with any combination of maple syrup, powdered sugar and fruits.
I used to put the butter in the baking dishes and set them in a warming oven to melt. However, with many of the new ovens there's a convection heating for preheat and it can get too hot causing Pyrex or similar dishes to break. To avoid that I melt my butter now in the microwave or even on the stove top first.