Spray your favorite casserole dish or 9x13 baking dish with olive oil spray. Add the bread cubes to the dish and set aside.
In a large bowl, add eggs, milk, cinnamon, sugar, vanilla and tangerine zest. Whisk well.
Evenly pour the mixture over the bread. Use a spatula or spoon to push the bread down.
Cover with plastic wrap and refrigerate overnight.
When you are ready to bake, preheat the oven to 350°F
Remove the baking dish from the refrigerator and let it sit while the oven is heating.
Bake covered for 30-45 minutes until casserole is set.
Uncover and bake for another 5 - 10 minutes.