Cinnamon Apple French Toast Casserole

Grease a 9x13 baking dish with cooking spray and preheat your oven to 350ºF.
Slice the bread into 1-inch cubes, and add to the 9x13 baking dish.
Sprinkle chopped pecans all over the top of the bread cubes.
Mix together the diced apples, melted butter, sour cream, sugar, brown sugar, corn starch, cinnamon, nutmeg, and lemon juice in a large mixing bowl.
Toss the apple mixture with the bread and pecans in the baking dish.
Whisk together the eggs, milk, vanilla extract, and salt in another large bowl.
Pour over the bread cubes and pecans in the baking dish, making sure all of the bread is soaked.
Cover with plastic wrap and chill for at least 4 to 6 hours or overnight.*
When you're ready to bake the casserole, remove it from the fridge, uncover it, and preheat the oven to 350° F.
In a small mixing bowl, cut cold sliced butter into the brown sugar, and cinnamon to make the topping.
Crumble or clump the topping over the entire breakfast casserole.
Cover with aluminum foil, and bake at 350° F for about 40 minutes. Then uncover and continue baking for an additional 15-20 minutes to let excess moisture out.
Once it's warmed through, golden on top, and crisp around the edges, remove it from the oven and let it cool for just a few minutes.
Then slice and serve with powdered sugar and/or maple syrup.