In a mixing bowl, whisk together pumpkin puree, sugars, eggs, vanilla, cornstarch, and spices until silky. Stir in the remaining cream.
4 Tbsp unsalted butter, 1 tsp flaky sea salt, 1.25 cups pumpkin puree, 0.5 cup granulated sugar, 0.25 cup brown sugar, 2 large eggs, 1 tsp vanilla extract, 1 tsp cornstarch, 1 tsp ground cinnamon, 0.5 tsp ground ginger