Using a stand mixer fitted with the paddle attachment (or a large bowl with a hand mixer or whisk), combine the pumpkin puree, egg whites, whole egg, Greek yogurt, applesauce, maple syrup, coconut sugar, vanilla extract, and melted butter (or coconut oil). Mix for 2 to 3 minutes until smooth.
1 cup pumpkin puree, 5 egg whites, 1 large egg, ¾ cup plain Greek yogurt, ½ cup unsweetened applesauce, ⅓ cup maple syrup, 1 tsp vanilla extract, 3 tbsp melted butter or coconut oil, ¼ cup coconut sugar