Preheat the oven to 375 degrees. Line a baking sheet with parchment paper or silicone mat.
In a medium bowl, mix together the flour, baking soda, and salt. Set that aside.
In a small bowl, mix together 1 tablespoon of cinnamon with ¼ cup of sugar. Mix well and set aside.
In the bowl of a stand mixer fitted with the paddle attachment, add the rest of the sugar and one stick of room temperature butter. Mix well until the butter and sugar are well combined.
Add the sourdough starter and eggs to the stand mixer. Mix again until fully combined. Scrape the sides of the bowl if necessary.
Add the flour to the stand mixer and mix until fully combined.
With an ice cream scoop, scoop a dough ball into the cinnamon and sugar mixture. Roll the dough in the cinnamon and sugar mixture. Place the dough ball on the prepared baking sheet. Continue until the baking sheet is full.
Bake for 10 minutes or until the cookies are slightly brown and soft. Allow the cookies to cool on a wire rack