In a medium bowl whisk together the all-purpose flour, baking soda, cinnamon, salt and nutmeg. Set aside.
In the bowl of a stand mixer fitted with the paddle attachment, beat together the butter, brown sugar and granulated sugar until creamy. Add the eggs and vanilla and mix until well combined, scraping down the sides of the bowl as needed.
With the mixer on low speed, mix in the flour mixture until just combined. Then mix in the oats and raisins on low speed.
Cover and refrigerate the cookie dough for 1-2 hours before baking. (Refrigerating the dough for much more than 2 hours can cause the edges of the cookies to brown before the centers are baked enough.)
When you are ready to bake the cookies, preheat oven to 350° F. Line baking sheets with parchment paper.
Scoop rounded tablespoon sized balls of dough, shape into balls and place on the parchment lined baking sheets.
Bake for 9-11 minutes, until barely golden brown around the edges and almost set in the center. Be careful not to over-bake the cookies. For the softest cookies you want to slightly under-bake. If baking two pans of cookies at once, rotate the pans halfway through the baking time.
Let cookies cool on baking sheet for 5-10 minutes, then remove to a wire rack to cool completely.