Preheat oven to 425°F (220 C) and position the rack in the middle of the oven.
In a large sauce pan on medium heat whisk together the brown sugar, granulated sugar, spices, salt, and cornmeal. Add in the pumpkin puree, bourbon, and vanilla whisking until smooth. Cook filling for 4-5 minutes slowly whisking until it begins to smoke, bubble softly and become fragrant.
Remove from heat. Whisk in the heavy cream, mascarpone, sour cream, and eggs until evenly distributed and smooth.
Pour the warm filling into the cold pie crust. Place the pie on a parchment paper lined baking tray.
Place pie on middle rack of the oven and bake for 15 minutes. Immediately lower the temperature to 350 F (180 C) and cook an additional 30-35 minutes until the most of the pie is set and the center has just a slight jiggle. Check your pie at the 20, 25, and 30 minute mark.
Place pie dish on cooling rack for 2-3 hours to completely cool and set.
Refrigerate for 2 hrs before serving. Store in an air tight container or covered with aluminum foil in the fridge for up to 5 days.