Overnight French Toast

From Bon Appetit

1/4 c butter at room temp
12 slices French bread loaf, 3/4-inch thick
6 eggs
1 1/2 c milk
1/4 c sugar
2 Tbs pure maple syrup
1 tsp vanilla
1/2 tsp salt
powdered sugar

Spread butter evenly over the bottom of a heavy large baking pan with 1-inch high sides. Arrange bread in pan.
Beat eggs, milk, sugar, syrup, vanilla and salt to blend in a large bowl. Pour mixture over bread. Turn bread slices to coat. Cover with plastic and refrigerate overnight.

Preheat oven to 350˚. Bake French bread 10 minutes. Turn bread over and continue baking until just golden, about 5 minutes (or more) longer. Transfer to plates and sprinkle with powdered sugar. Serve immediately.