Buttermilk French Toast

Ingredients:

•  1 1/2 cups well-shaken buttermilk
•  4 large eggs
•  3 tablespoons sugar
•  1/4 teaspoon salt
•  12 (1/2-inch-thick) slices challah (from a 1-pound loaf; not end slices)
•  4 1/2 tablespoons unsalted butter, divided

Preparation:

•  Whisk together buttermilk, eggs, sugar, and salt in a bowl. Pour into a large 4-sided sheet pan, then add bread in 1 layer and soak, turning occasionally, until bread has absorbed all liquid but is not falling apart, about 20 minutes.
•  Heat 1 1/2 tablespoon butter in a 12-inch nonstick skillet over medium-high heat until foam subsides. 
•  Transfer 4 bread slices with a slotted spatula to skillet and cook, turning once, until slightly puffed and golden brown, about 3 minutes total. Transfer to a large shallow baking pan and keep warm in oven. Cook remaining bread in 2 batches, adding 1 1/2 tablespoon butter between batches.