Place granulated sugar and orange zest in a medium bowl. Use your fingers to mix the sugar and zest together until fragrant. Add the cranberries and stir to combine. Set aside.
2 tablespoons granulated sugar, zest of 1 large orange, 1 cup fresh cranberries
Spray a 9x13 rectangular baking dish with cooking spray. Place the bread cubes in the dish and arrange them into an even layer as much as possible.
1 loaf day-old French bread*
In a large bowl or large liquid measuring cup or batter bowl (for easy pouring), combine the eggs, milk, maple syrup, vanilla, and 1 teaspoon cinnamon. Whisk until well combined and then pour evenly over the bread in the dish.
6 large eggs, 2 cups whole milk, ½ cup pure maple syrup, 1 tablespoon vanilla extract, 1 teaspoon ground cinnamon
Sprinkle the cranberry-orange sugar mixture evenly over the top.
To make the streusel, stir together the flour, brown sugar, and ½ teaspoon cinnamon in a medium bowl. Add the butter pieces and then use a pastry blender or your fingers to work the butter into the flour mixture until the butter pieces are no bigger than small peas and the mixture begins to clump together. Sprinkle over the top of the casserole.
⅓ cup all-purpose flour, 3 tablespoons packed light brown sugar, ½ teaspoon ground cinnamon, ¼ cup cold unsalted butter
Cover the French toast with plastic wrap and refrigerate overnight.
When you are ready to bake the casserole, preheat your oven to 350° F. Once the oven is preheated, remove the plastic wrap from the casserole and cover it with foil. Bake, covered for 30 minutes. Remove the foil and continue to bake for another 20-30 minutes, until lightly golden on top and set in the center. Serve and enjoy!