Preheat oven to 350 degrees F. Line two baking sheets with parchment.
In the bowl of a stand mixer, beat the butter and sugar until light and fluffy. Gradually beat in the maple syrup, scraping sides of the bowl. Add the egg and vanilla and beat until blended.
In a separate bowl, mix together the flour, baking soda, salt, cinnamon, and nutmeg, then add to the butter mixture and stir util blended. Stir in oats, raisins and nuts (if using).
Divide dough into about 20 to 21 balls and arrange on parchment lined baking sheets. Flattento ½ inch disks. Alternatively, arrange your dough balls on dinner plates lined with plastic wrap and cover and chill until ready to bake.
Bake cookies 15-17 minutes (will take slightly longer with cold dough), rotating the sheets halfway through, until golden brown and just barely set in the middle. Let cool completely. You can let them cool completely on the tray for chewier cookies or let them cool briefly on the tray and transfer to a wire rack.