In a stand or a hand-held mixer, cream together the butter, brown sugar, and white granulated sugar.

Add in the eggs and vanilla extract.

Set the mixing speed to medium-low and add in the flour ½ cup at a time.

After you have added all of the flour, add in the baking soda, ground cinnamon, nutmeg, and salt.

Fold in the old-fashioned oats using a plastic spatula or a spoon.

Cover the mixing bowl with plastic wrap and let the cookie dough chill in the refrigerator a minimum of 2 hours, however, 24 hours is best.

Preheat oven to 350 degrees and line a cookie sheet with parchment paper or a silicon baking mat.

Spoon the cookie dough, then roll with your hands and flatten down. It will look like round and flat.

Bake for 10-12 minutes. 10 minutes was perfect for me.

Let the cookies cool for 1-2 minutes, then transfer to a cooling rack.