Preheat the oven to 350 F. In a medium bowl, whisk together flour, salt, and baking soda. In a large bowl, combine butter with sugar until fluffy. Add in egg and vanilla extract, and mix until smooth.
Add in the flour mixture, mix until it is fully combined. Divide the cookie dough into two bowls, color one half of the cookie dough blue, and the other half of the dough green. In a shallow dish, combine granulated sugar and ground cinnamon.
Take a piece of both colors of cookie dough, and roll them together into a ball. Roll each ball into the cinnamon sugar mixture. Place the cookies onto a large ungreased baking sheet. Bake for 10-12 minutes.
