In a large mixing bowl, cream together the softened unsalted butter, white sugar, and light brown sugar. Beat the mixture on medium-high speed until it becomes light and fluffy, which should take about 2-3 minutes. This step will help the cookies have a tender texture.

Add the pure maple syrup, vanilla extract, and egg to the creamed butter and sugar mixture from Step 1. Beat again on medium speed until everything is well incorporated and the mixture is smooth.

In a separate bowl, sift together the baking soda, all-purpose flour, ground cinnamon, cream of tartar, and salt. Gradually add the dry ingredients to the wet ingredients from Step 2, mixing until just combined and a soft dough forms.

Cover the bowl with the cookie dough from Step 3 and refrigerate for at least 1 hour. Chilling the dough helps prevent the cookies from spreading too much in the oven. Personally, I find that overnight chilling makes the flavors even richer.

Preheat your oven to 375°F (190°C) and line a baking sheet with parchment paper to prevent sticking.

In a small bowl, mix together the granulated sugar and ground cinnamon to make the cinnamon sugar. Scoop the chilled dough from Step 4 and roll into 1 1/2-inch balls. Roll each ball in the cinnamon sugar mixture until fully coated.

Place the cinnamon sugar-coated dough balls from Step 6 about 2 inches apart on the prepared baking sheet. Bake in the preheated oven for 8-10 minutes, or until the tops have cracked and the cookies are set. Remove from the oven and let cool on the baking sheet for a few minutes before transferring to a wire rack to cool completely.