Preheat oven to 350°F. In a small bowl, whisk together the flour, baking soda, salt, and cinnamon; set aside. In a large mixing bowl, place the butter and both sugars. Use a handheld or stand mixer (or your strong arm!) to combine and beat until slightly fluffy. Beat in the eggs until well mixed, about 1 minute. Dump in the flour mixture, and mix that until just combined. Stir in the chocolate.
Form rounded teaspoon-size balls of dough and place them about 3 inches apart on parchment-lined baking sheets.
Bake until cookies are golden brown 12 to 15 minutes. Remove from the oven, and let cool on baking sheet 1 to 2 minutes. Slide the parchment onto wire racks, then let the cookies cool completely. Repeat with any remaining dough.
Store cooled cookies in an airtight container at room temperature up to 1 week.
Recipe by Big Girls Small Kitchen at http://www.biggirlssmallkitchen.com/2016/05/thin-crispy-cinnamon-milk-chocolate-cookies.html