Preheat oven to 375°F (190°C). Line baking sheets with parchment paper.
In a large bowl, cream together the butter, sugar, and maple syrup until light and fluffy. Beat in the eggs one at a time.
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 the dough into 1-inch balls and then roll in the cinnamon-sugar mixture. Place on the prepared baking sheets.
Bake for 8-10 minutes, or until the edges are lightly golden brown. Let cool on baking sheets for a few minutes before transferring to a wire rack to cool completely.
Notes
Enjoy these warm with a glass of milk or a cup of coffee!