Preheat oven to 350 degrees F (175 degrees C). Line rimmed 18 by 13-inch baking sheets with parchment paper or silicone baking mats.

In a mixing bowl whisk together flour, cinnamon, baking soda, baking powder and salt for 20 seconds, set aside.

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

Mix in one egg, then blend in second egg and vanilla.

Add flour mixture and mix just until combined then mix in oats, raisins and walnuts.

Scoop dough out and shape into 1.5-inch balls (or 40 grams each), transfer to prepared baking sheet fitting 12 per sheet and spacing 2-inches apart.

Bake in preheated oven until golden brown on edges and nearly set (center should look under-baked), about 12 - 14 minutes.

Let cool on baking sheet for a few minutes then transfer to a wire rack to cool completely. Repeat with remaining dough.

Store in an airtight container at room temperature.