Preheat oven to 350°F (175°C). Line baking sheets with parchment paper.
In a large bowl, cream the butter, brown sugar, and granulated sugar until light and fluffy (about 2–3 minutes).
Add the pumpkin puree, egg, and vanilla extract, and beat until smooth.
In a separate bowl, whisk together the flour, baking soda, salt, cinnamon, nutmeg, cloves, and ginger.
Gradually add the dry ingredients to the wet mixture and mix until just combined.
Stir in the oats, and if using, fold in raisins, chocolate chips, and/or nuts.
Drop spoonfuls (about 1.5 tablespoons) of dough onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 12–14 minutes, or until the edges are lightly golden and centers look set but soft.
Let the cookies cool on the pan for 5 minutes before transferring them to a wire rack.