Preheat your oven to 300° F and toast the challah pieces on a sheet tray for 5 minutes. Flip the challah pieces and continue to toast for another 3-5 minutes.
While the challah is toasting, combine the eggs, milk, orange juice, vanilla extract, salt, sugar and zest in a medium size bowl and whisk until combined well.
Spray a 9x13 inch pan and transfer the toasted challah pieces there. You can just throw the pieces inside, no need to arrange in any specific way.
Pour the egg mixture over the challah and press down slightly to make sure all the pieces will absorb the mixture.
Cover with plastic wrap and leave overnight or at least 2 hours.
In the morning, preheat your oven to 350° F. Sprinkle the top of the french toast with chocolate chips (optional or melt the chips and drizzle on top once baked) cover with foil and bake for 20-25 minutes.
Uncover and bake for another 20 minutes until the top is golden brown and the egg mixture is set.
Top with maple syrup, confectioners sugar, and fresh orange slices.
Notes
This needs time to soak up all the flavors, so don't be tempted to bake right away!Try it with berries instead!!