Arrange bread slices in a 13- x 9-inch baking dish.
Whisk together eggs, next 4 ingredients, and, if desired, liqueur; pour over bread. Let stand 5 minutes, turning once. Cover and chill 8 hours, if desired.
Melt butter at 400° in a 15- x 10-inch jellyroll pan; add French bread slices.
Bake at 400° for 15 minutes; turn and bake 8 to 10 more minutes or until golden. Sprinkle with almonds and powdered sugar. Serve with maple syrup.