Blueberry Brown Oat Cookies

1. Preheat oven to 350ºF.
2. Brown butter in a medium saucepan over medium heat for about 7 minutes, until foam is gone and brown specks appear.
3. Place brown sugar in a large mixing bowl, and once butter is browned, immediately pour over sugar. Let butter cool into the sugar for about 10 minutes.
4. Meanwhile, combine flours, oats, cinnamon, salt, baking powder, and baking soda in a small mixing bowl and mix well.
5. Once butter mixture is cooled, add egg and beat until well-incorporated. Add vanilla.
6. Add half of the flour mixture to the wet ingredients, stirring thoroughly but not too much, until just incorporated. Add the other half of flour mixture, following same technique. Dough should be sticky and not at all runny—if it is, add more all-purpose flour, one tablespoon at a time, until dough is thick and drier.
6. Gently stir in blueberries and walnuts, if desired, until well distributed, and place in the refrigerator to cool, about 10 minutes.
7. Spoon dough onto a parchment-paper lined baking sheet, about 1 inch in diameter and somewhat rounded. Bake for approximately 8 minutes, or until cookies appear brown on edges and small bubbles appear in the middle.