Prepare pan and preheat. Position a rack in the center of the oven. Preheat oven to 350°F (180°C). Butter or lightly grease a 9x13 baking dish with cooking spray.
Prepare bread. Tear bread into 1-inch pieces. Place torn pieces of bread into the bottom of the casserole dish.
Combine wet ingredients. In a large bowl, whisk together the heavy cream, half and half, pumpkin puree, granulated sugar, melted butter, eggs, vanilla, pumpkin pie spice, and cinnamon.
Pour over bread. Slowly pour the wet mixture over the bread pieces in the baking dish. Be sure to cover all the bread pieces. I like to squish the bread pieces on top to make sure it's soaked.
Bake your bread pudding. Bake in a preheated oven for about 1 hour on middle rack until the custard is set. The top bread pieces should be golden brown.
Make praline sauce. While the bread pudding is baking, make the praline sauce. In a heavy saucepan over medium heat, stir together the butter, heavy cream, and brown sugar; bring to a boil. Reduce heat to low, and stir in pecans. Simmer until the sauce thickens, for about 5-7 minutes. Remove the saucepan rom the heat and stir in the vanilla. If not using right away, cover and refrigerate. Warm back up again before serving. Serve the sauce over bread pudding.