In a medium bowl, whisk together the flour, salt, baking soda, cinnamon and nutmeg.
Cream the butter in a mixer on medium speed. Add the sugars and mix for 3-4 minutes until light and fluffy. Scrape down the sides of the bowl.
Add the egg and vanilla extract. Mix on low until just combined.
Slowly add the dry ingredients on low speed. Mix until just combined.
Add the oats to the mixer bowl and slowly mix in, do not overmix. If needed, mix by hand. Add in the raising and mix until just combined.
Refrigerate dough for 30 minutes, but not more than 45 minutes.
Preheat oven to 325 degrees F.
Using an ice cream scoop, scoop out leveled amounts of dough and place on a parchment or silpat-lined baking sheet, about 3-4 inches apart. This will make large, bakery style cookies.
Bake at 325 degrees for 20-22 minutes. Remove from oven and let cookies rest on baking sheet for 10 minutes and then transfer to wire rack to cool.