In a large bowl, whisk together the pumpkin purée, eggs, egg yolk, brown sugar, granulated sugar, pumpkin pie spice, cinnamon, cardamom, salt, and cornstarch until smooth.
15 oz 1 can pumpkin purée, 2 large eggs, 1 egg yolk, ¾ cup packed brown sugar, ¼ cup granulated sugar, 2 tsp pumpkin pie spice, ½ tsp ground cardamom, 1 tbsp cornstarch, ¼ tsp salt