Combine the sugar, dry milk, and xanthan gum in a small bowl and stir well.
Pour the corn syrup into a medium pot and stir in the whole milk. Add the sugar mixture and immeditately whisk vigorously until smooth. Set the pot over medium heat and cook, stirring often and adjusting the heat if necessary to prevent a simmer, until the sugar has fully dissolved, about 3 minutes. Remove the pot from heat
Add the cream and whisk until fully combined. Transfer the mixture to an airtight container and refrigerate until well chilled, at least 6 hours, or for even better texture and flavor, 24 hours. Stir the base back together if it separates during the resting time. The base can be further stored in a fridge for up to 1 week or in the freezer for up to 3 months.