Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.
In a large bowl, cream together the butter and sugar until light and fluffy. Beat in the maple syrup, eggs, and vanilla extract.
In a separate bowl, whisk together the flour, cream of tartar, baking soda, and salt. Gradually add to the wet ingredients, mixing until just combined.
In a small bowl, combine the sugar and cinnamon for the coating.
Roll dough into 1-inch balls and coat in the cinnamon-sugar mixture. Place on prepared baking sheets.
Bake for 8-10 minutes, or until edges are lightly golden. Let cool on baking sheets for a few minutes before transferring to a wire rack to cool completely.
Notes
For best results, use pure maple syrup. Store in an airtight container at room temperature.