1. Preheat oven to 250° F.
2. In a large shallow baking dish whisk together eggs, orange juice, milk, liqueur, brown sugar, and nutmeg. Add 4 bread slices and soak 2 minutes. Turn slices over and soak 2 minutes more. Transfer soaked bread slices to a tray and repeat procedure with remaining 4 bread slices.
3. In a large heavy skillet heat 1 1/2 tablespoons butter over moderate heat until foam subsides and cook half of coated bread slices until golden, about 3 minutes on each side. Transfer French toast as cooked to a baking sheet and keep warm in oven. Cook remaining bread slices in same manner.
4. Dust French toast with confectioners' sugar and serve with syrup.