Melt the butter in a heavy-bottomed sauce pan over medium heat. Add the maple syrup and brown sugar, whisking to combine. Pour the mixture into the bottom of a 9x13-inch baking dish.

Place the cubed bread on top of the butter/sugar mixture in an even layer.

Whisk the milk, eggs, pumpkin, vanilla extract, 1 teaspoon of the pumpkin pie spice, and a pinch of kosher salt together until very well combined. Pour the mixture over the cubed bread, making sure to soak all of the bread. Press the bread down into the milk mixture with a spatula, if necessary, to ensure that all of the bread is moistened.

If making this ahead of time, cover the dish and stash it in the fridge. When you're ready to bake the bread pudding, preheat the oven to 350 degrees F.

When ready to bake, sprinkle 1 tablespoon of brown sugar and the remaining 1 teaspoon of pumpkin pie spice over the top of the bread pudding in an even layer.

Bake for 30-40 minutes, or until the center is set and reaches 160 degrees F.

Remove it from the oven and dust the top with powdered sugar. Drizzle additional maple syrup over the top, if desired.