Preheat over to 375. In a bowl,whisk together the sugar and melted butter. Spread the mixture in a large rimmed baking pan. Set aside.
In a large bowl, whisk together the milk,eggs,vanilla,lemon juice,cinnamon,salt and cayenne pepper. Dip each slice of bread in the egg mixture and soak for 30 seconds. Transfer to the baking pan. Bake for 25 minutes or until golden,turning halfway through baking.