Add pumpkin puree and pumpkin pie spice to a saucepan over medium heat.
Cook, stirring constantly, for 3-5 minutes until cooked, fragrant, and deeper orange in color (but not brown!).
Pour in coconut milk and xylitol, and mix thoroughly.
Cook just until the xylitol dissolves and everything is well incorporated.
Remove from heat, stir in vanilla extract and salt, and allow the mixture to come to room temperature.
Place cream cheese in a large mixing bowl and pour in the pumpkin mixture.
Whisk until the cream cheese is (absolutely!) fully blended.
This is faster with an electric whisk or mixer, but also doable by hand.
Stir in whipped sour cream and taste for sweetness.
This is your last chance! We find that 1/2 cup of xylitol is more than enough, but up to 3/4 cup will work too.
Remember that things taste less sweet when frozen, so you'll want to turn it up a notch.
If no ice cream maker is at hand, place ice cream in sealable container and place in the freezer until frozen (6 hours to overnight).
Or churn in an ice cream maker following manufacture's instructions (about 15 minutes).
If you like your ice cream firmer, freeze in the covered container for one to two hours.