Heat oven to 350°.
In a bowl, combine the flour, baking soda, salt and cinnamon and nutmeg (if using).
In a separate bowl, beat the butter and sugars until creamy.
Add the egg and vanilla and beat well.
Add the flour mixture and mix well.
Add the oats; combine thoroughly.
Stir in raisins or chips (if using).
Drop dough in rounded tablespoonfuls onto ungreased cookie sheets. Flatten lightly with the palm of your hand.
Bake for 9 to 11 minutes. Cool for 2 minutes on the cookie sheet; remove to wire rack to cool completely.