Before we get into the recipe, let's talk about the type of bread you need. What we prefer to use is a 28oz loaf of Innkeeper's Cinnamon Streusel Bread (I buy it at Costco). Do you have to? Absolutely not. You can use any type of Cinnamon or Streusel Bread. If you can't find that, you could use regular bread. My recommendation for regular bread is something like a Brioche that's a little denser. If you don't use something with added Cinnamon or Streusel, double the amount of Sugar & Cinnamon in the egg mixture.
In a buttered 9"x13" baking dish, add your Cubed Bread and Apples. Mix together.
In a separate bowl, whisk together Eggs, Milk, Sugar, 1 tsp Cinnamon, Vanilla & Salt. Pour over Bread, cover with foil or plastic and place in fridge at least 6 hours, preferably overnight.
The next morning remove from fridge. While oven is preheating to 350, sprinkle the top lightly with Brown Sugar & Cinnamon (to your taste).
Bake uncovered for 50-55 minutes.