Use a serrated knife to cut bread into 8 diagonal slices, each ¾ -inch thick.
Place eggs in medium bowl and whisk until smooth. Crumble the brown sugar to remove lumps into eggs; add orange juice, amaretto, milk, vanilla, and salt. Whisk until well blended.
Dip each slice of bread into the egg mixture, turning to coat completely. As bread is dipped, place in a baking dish in an even layer. Pour remaining egg mixture over the bread and allow bread to soak. (This may be done the night before - cover and place in refrigerator.)
Preheat your Griddler™ fitted with the griddle plates in the open griddle position to 325°F. Brush both sides of each soaked slice of bread with melted butter. Arrange on hot Griddler and cook until golden brown on both sides, about 2 to 3 minutes per side.
Sprinkle with powdered sugar. Serve hot with Maple Peach Syrup.