Cut the butter into pats and arrange in a 9×13 inch baking dish. Preheat oven to 425 degrees F and place baking dish in oven just until the butter melts.
As butter melts, combine eggs, milk, flour, salt, cinnamon, and vanilla in blender and pulse until evenly combined and smooth.
Pour the batter over the melted butter and bake for 22 minutes or until edges have puffed up and started to turn brown.
Cut into slices to serve and top with powdered sugar, syrup, whipped cream, fruits, etc.
