Melt butter in a 9x13 pan while oven preheats.
Heat oven to 425 F.
In a blender, mix eggs and milk; add flour and salt and blend again. Pour mixture into pan with melted butter.
Bake 15-20 minutes. The batter will rise but not run over. Cut in squares and serve as French toast with syrup and powdered sugar.
Adapted from Real Mom Kitchen