1/2 cup unsalted butter
1 cup packed brown sugar
2 Tbsp corn syrup (or honey)
1 (8 - 9") round loaf Challah bread
5 large eggs
1 1/2 cups half and half
1 tsp vanilla
1 tsp concentrated orange juice
1/4 tsp salt
In small heavy saucepan, melt butter with brown sugar and corn syrup over moderate heat, stirring until smooth and pour into a 13 x 9" baking dish.
Cut 6 (1" thick) slices from center portion of bread, reserving ends for another user, and trim crusts.
Arrange bread slices in one layer in baking dish, squeezing slightly to fit. In a bowl, whisk together eggs, half and half, vanilla, orange juice, and salt until combined well and then pour over bread. Chill bread mixture, covered, at least 8 hours and up to 1 day.
Preheat oven to 350 degrees and bring bread to room temp. Bake bread mixture, uncovered, in middle of oven until puffed and edges are pale golden (35 - 40 mins).