Preheat oven to 350 degrees F if baking the same day.
Casserole
In a large bowl, whisk together the pumpkin, milk, eggs, 1/2 cup brown sugar, vanilla, pumpkin pie spice, 1 tsp of cinnamon and salt.
Cut the bread into bite-sized pieces. Add the bread cubes to the pumpkin custard mix and stir to combine. Let it sit in the bowl and stir a couple of more times while you prepare the topping.
Topping
In a microwave safe bowl, melt the butter.
In a larger clean bowl, stir together the melted butter, remaining 1/2 c of brown sugar, pecans and 1/2 teaspoon of cinnamon until well combined.
Spoon the bread casserole mixture evenly into an 8x8 casserole dish.
Evenly spread the topping mixture over the top. I use a fork for this.
Bake for 45 minutes.
Or, cover the dish tightly with plastic wrap and store in the refrigerator overnight.
The next morning, remove the plastic and bake uncovered at 350 degrees F for 50 minutes.