In the bowl of a stand mixer fitted with a paddle attachment, cream butter, sugar, and vanilla extract until well-combined and fluffy. Note: you can also mix the ingredients by hand in a large mixing bowl, or you can use an electric hand mixer. Scrape the sides of the bowl with a rubber spatula and add the egg. Beat until the wet ingredients are completely combined.
In a separate medium bowl, stir together the oat flour, ground cinnamon, baking powder, baking soda, and sea salt.
Cover the bowl with plastic wrap and refrigerate the cookie dough for 30 minutes.
When you’re ready to bake the cookies, preheat the oven to 350 degrees Fahrenheit and line a large baking sheet with parchment paper.
Bake cookies for 9 to 11 minutes or until the edges are slightly golden brown and they reach your desired level of doneness.
Allow the cookies to cool for at least 10 minutes before serving. If you have a cooling rack, feel free to move the cookies over after 10 minutes of cooling.
