In a small saucepan, heat heavy whipping cream, brown sugar, pumpkin puree, pumpkin pie spice, and vanilla extract over low-to-medium heat, whisking frequently until brown sugar and pumpkin puree has dissolved and disintegrated. Transfer to jar to cool.
Once pumpkin cream has cooled, add ice to coffee mug and pour in cold brew 3/4 of the way up.
Add pumpkin cream mixture to fill.
Top with whipped cream and a sprinkle of pumpkin pie spice. Enjoy!