8 to 10large slices hearty white sandwich bread or good-quality challah
1 ½cupswhole milkwarmed*
3large egg yolks
3tablespoonslight brown sugar
2tablespoonsunsalted buttermelted, plus 2 tablespoons for cooking
Adjust oven rack to middle position and heat oven to 300°F/150°C. Place bread on wire rack set in rimmed baking sheet. Bake bread until almost dry throughout (center should remain slightly moist), about 16 minutes, flipping slices halfway through cooking. Remove bread from rack and let cool 5 minutes.
Preheat griddle to 350°F/175°C. Whisk milk, yolks, sugar, cinnamon, 2 tablespoons melted butter, salt, and vanilla in large bowl until well blended. Transfer mixture to 13- by 9-inch baking pan.
Soak bread in milk mixture until saturated but not falling apart, 20 seconds per side. Using firm slotted spatula, pick up bread slice and allow excess milk mixture to drip off; repeat with remaining slices. Place soaked bread on another baking sheet or platter.
Use a slotted spatula to transfer soaked bread to griddle and cook until golden brown, 5 to 6 minutes. Flip and continue to cook until second side is golden brown, 5 to 6 minutes longer. (If toast is cooking too quickly, reduce temperature slightly.) Serve warm.
*To prevent the butter from clumping during mixing, warm the milk in a microwave or small saucepan until warm to the touch (about 80 degrees).
*For best results, choose a good challah or a firm, high-quality sandwich bread, such as Arnold Country Classics White or Pepperidge Farm Farmhouse Hearty White. Thomas’ English Muffin Toasting Bread also works well. If you purchase an unsliced loaf, cut the bread into 1/2-inch-thick slices.