Mix 1/4 cup soy creamer with arrowroot and set aside.
Whisk together 1 3/4 cup soy creamer, soy milk, brown sugar, pumpkin puree, vanilla extract, and pumpkin pie spice in a saucepan over medium heat, stirring frequently, until just boiling.
Remove the pan from the heat; stir in the arrowroot mixture to thicken. Set aside to cool for 30 minutes.
Fill cylinder of ice cream freezer; freeze according to manufacturer's directions.