Step 1

Preheat oven to 375 degrees. Add oats to a food processor. Process oats until they are very finely ground, nearly to a flour, about 2 - 3 minutes.

Step 2

Add ground oats to a large mixing bowl along with flour baking soda, baking powder and salt. Whisk 20 seconds. Set aside.

Step 3

In the bowl of an electric stand mixer fitted with the paddle attachment cream together butter, brown sugar and granulated sugar until well combined.

Step 4

Mix in eggs one at a time then blend in vanilla. With mixer set on low speed slowly add in dry ingredients and mix just until nearly combined.

Step 5

Add in chocolate chips, chopped chocolate and walnuts if using and mix (you can set a few chocolate chips aside first if you want some to press into tops of dough for looks).

Step 6

Scoop dough out 2 oz. at a time (nearly 1/4 cup) and shape into rounds (at higher altitude I recommend making taller dough balls, so more of an oval shape, for less spread).

Step 7

Transfer 9 dough balls to an 18 by 13-inch baking sheet lined with a silicone liner or parchment paper, spacing them about 3-inches apart (refrigerate dough that's not currently baking).

Step 8

Bake in preheated oven until nearly set but slightly under-baked, about 10 minutes.

Step 9

Let cool several minutes on baking sheet then transfer to a wire rack to cool. Repeat process with remaining dough. Store cookies in an airtight container.