Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper.
In a mixing bowl, cream together the vegan butter and 1.5 cups of sugar until light and fluffy.
Add the non-dairy milk and vanilla extract, and mix until combined.
In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
In a small bowl, mix together the 2 teaspoon of ground cinnamon and 0.25 cup of sugar.
Roll the dough into 1.5-inch balls, then roll each ball in the cinnamon-sugar mixture to coat.
Place the dough balls on the prepared baking sheet, spacing them about 2 inches apart.
Bake for 10 minutes, or until the edges are lightly golden. Let cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.