In a large bowl, toss together the bread, raisins and pecans until evenly combined. In a separate bowl, whisk together the half and half, cream, both sugars, eggs, egg yolks, vanilla, cinnamon, salt and butter. Pour over the bread mixture and stir until evenly combined. Transfer to a greased 7-inch round casserole or soufflé dish, pressing down firmly. Grease a piece of foil with cooking spray and cover the bread pudding tightly with the foil, greased side down.
Place a wire trivet inside of a 6-quart or large Instant Pot and pour in 1 ½ cups of water. Carefully place the bread pudding inside, lock the lid and set the valve to seal. Pressure cook on high for 42 minutes. Allow the pressure to naturally release for 10 minutes before manually releasing any residual pressure. Carefully unlock the lid, lift out the bread pudding and set aside.
Remove the trivet and pour out the water. Return the bowl to the Instant Pot and press the sauté button on low. Add the butter and allow to melt. Whisk in the sugar and cook until it has dissolved. Pour in the cream, bourbon, vanilla and salt and cook, stirring constantly, until the mixture thickens and begins to bubble. Turn off the machine. Serve the bread pudding warm by scooping it into bowls and drizzling the sauce over it.