Spray an 8 x 8 baking dish with cooking spray.
Cut the bread into 1 inch cubes and place in the baking dish.
Add the chopped apples and mix well to combine.
In a medium sized mixing bowl beat the eggs. Add in the milk, sugar, vanilla, cinnamon, allspice, and salt and mix well.
Pour the mixture over top of the bread and apples in the baking dish. Toss to combine.
At this point you can cover the baking dish and refrigerate for up to 24 hours or you can preheat the oven to 375 degrees.
Bake the French toast casserole for 20 minutes.
Meanwhile, in a medium mixing bowl combine all the ingredients for the streusel and mix until a chunky mixture forms.
After baking for 20 minutes remove from oven and evenly sprinkle the streusel on top.
Return to oven and continue baking for 20 more minutes.
Remove from oven and drizzle with the caramel sauce.