Spray a 9x13" baking dish with non-stick cooking spray and place bread cubes in dish- you want enough bread to fill the dish almost completely full
In a large bowl, whisk together eggs, milk, vanilla, syrup, 1 Tablespoon brown sugar and pumpkin puree until well combined. Pour over bread and mix with the bread (I used my hands, but you could use a large spoon) until all the bread is mostly covered. Cover with plastic cling wrap or lid and refrigerate overnight (if you wanted to, you could also bake it at this time instead of letting it sit overnight).
In the morning, preheat oven to 350 degrees, uncover and top with brown sugar and nuts (optional). Bake for 35-45 minutes or golden brown and no longer wet.
Serve immediately with maple syrup, honey or agave nectar. Store leftovers in the refrigerator covered for up to a couple days.