In a bowl whisk together rolled oats, all purpose flour, salt, cinnamon powder and baking soda. Set aside.
In the steel bowl of your stand mixer fitted with paddle attachment or using your stand mixer beat together butter and both the sugars, scraping the sides of the bowl with a spatula till creamy and smooth, around 3 minutes.
Add the vanilla extract, egg and mix.
Now add the oats-flour fix in parts, mixing well after each addition.
Stir in raisins and chopped pecans/walnuts.
Take 1/4 cup of the dough per cookie. Make 11-12 large cookie balls and place them on a baking sheet. Press few raisins on top of each cookie ball [optional]
Place the baking sheet with the cookie dough balls in the refrigerator for minimum of 2 hours, or overnight. Chilling the dough is mandatory.
Preheat oven to 350 F degrees.
Bake the chilled cookie dough balls for 14-15 minutes [personal preference] or for 11 minutes for softer cookies.
Let the cookies cool down in the pan for 10 minutes before transferring them onto a wire rack to cool completely.