01 - Preheat oven to 350°F. Line two baking sheets with parchment paper.
02 - Whisk together flour, baking soda, salt, cinnamon, nutmeg, and oats in a medium bowl.
03 - In a large bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy.
04 - Beat in the eggs one at a time, then add the vanilla extract.
05 - Gradually incorporate the dry ingredients into the wet mixture, stirring until just combined.
06 - Fold in the raisins and walnuts, if using.
07 - Drop rounded tablespoons of dough onto prepared baking sheets, spacing about 2 inches apart.
08 - Bake for 10 to 12 minutes until edges are golden and centers remain soft.
09 - Allow cookies to cool on the baking sheets for 5 minutes before transferring to wire racks to cool completely.