Make the brown butter (I used the technique from The Kitchn)

1. In a small saucepan, melt the butter over medium heat. Tip – Use a pan with a light-colored bottom so you can see the color of the butter change.
2. Swirl the pan while the butter is cooking so it cooks evenly.
3. The butter will begin to foam as it melts and the color will change to a light brown. Once you smell the nutty aroma, take the pan off the heat and pour the browned butter into a glass bowl. Set aside.

Make the Cookie Dough

1. In a medium bowl, combine the dry ingredients; oat flour, almond flour, 2 teaspoons cinnamon, baking soda, raw sugar, and salt. Mix until combined and set aside.
2. In a small bowl, combine the wet ingredients (minus the butter); milk, vinegar, and vanilla extract.
3. Gently pour the wet ingredients into the dry ingredients. Mix to combine. 
4. Add the brown butter to the batter and gently mix again until well incorporated.
5. Place the batter in the fridge for 30 minutes or up to 24 hours (see notes). 
6. While the batter is in the fridge, preheat the oven to 350°F and grease or line a cookie sheet with parchment paper. Set aside.
7. Remove the batter from the fridge. Using a medium size cookie scoop, scoop the batter into your hands and roll into a ball. Roll each dough ball into the cinnamon-sugar mixture then place on the baking sheet. With a spoon, sprinkle each dough ball with additional cinnamon sugar.
8. Bake for 11 to 14 minutes. Check at 10 minutes for doneness. Remove cookies from the oven and allow them to cool on the pan for 8-10 minutes before transferring to a wire rack to cool completely.
9. Store cookies at room temperature in an airtight container for up to 5 days.