(from americastestkitchen.com)

   French Toast for Challah or Sandwich Bread

   Makes 4 or 5 slices from Challah or 6 to 8 slices from Sandwich Bread

   Though thick-sliced challah is best for French toast, you can
   substitute high-quality, presliced sandwich bread. Flipping challah is
   easiest with tongs, but a spatula works best with sandwich bread. To
   speed the cooking of large quantities of French toast, heat two or
   more skillets to brown a few batches at once. To vary the flavor of
   the batter, try adding 3/4 teaspoon ground cinnamon or 1/2 teaspoon
   ground nutmeg with the dry ingredients, or try substituting almond
   extract for the vanilla extract.

   1 large egg
   2 tablespoons unsalted butter, melted, plus extra for frying
   3/4 cup milk
   2 teaspoons vanilla extract
   2 tablespoons sugar
   1/3 cup all-purpose flour
   1/4 teaspoon salt
   4-5 slices day-old challah, cut 3/4 inch thick, or 6 to 8 slices
   day-old sandwich bread

   1. Heat 10- to 12-inch skillet (preferably cast iron) over medium heat
   for 5 minutes. Meanwhile, beat egg lightly in shallow pan or pie
   plate; whisk in butter, then milk and vanilla, and finally sugar,
   flour, and salt, continuing to whisk until smooth. Soak bread without
   oversaturating, about 40 seconds per side for challah or 30 seconds
   per side for sandwich bread. Pick up bread and allow excess batter to
   drip off; repeat with remaining slices.

   2. Swirl 1 tablespoon butter in hot skillet. Transfer prepared bread
   to skillet; cook until golden brown, about 1 minute 45 seconds on
   first side and 1 minute on second side. Serve immediately. Continue,
   adding 1 tablespoon butter to skillet for each new batch.