Combine the sugar, dry milk, and xanthan gum in a small bowl and stir well.
½ cup granulated sugar, 2 tbsp dry milk powder, ¼ tsp xanthan gum
Pour the corn syrup into a medium pot and stir in the whole milk. Add the sugar mixture and immediately 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 the heat.
2 tbsp light corn syrup, 1⅓ cups whole milk
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 the fridge for up to 1 week or in the freezer for up to 3 months. (Just be sure to fully thaw the frozen base before using it.)
1⅓ cups heavy cream