Preheat oven to 350 ° F. Grease baking sheets with butter or spray with Pam.
In a large mixing bowl, cream butter with sugar until fluffy. Stir in pumpkin, egg and vanilla.
In a separate bowl, sift together flour, baking soda, baking powder, cinnamon, nutmeg and salt.
Add dry ingredients to butter mixture, stirring well to combine. Stir in chocolate chips and nuts or raisins, if using. Drop batter by spoonfuls on to baking sheets.
Bake for 12-15 minutes or until browned. Cool on rack.