Whisk the flour, cornstarch, baking soda, baking powder, cinnamon, ginger, nutmeg, cloves, and salt together in a medium bowl until the spices are evenly scattered through the flour.

In a large bowl, whisk the melted vegan butter with the brown sugar and granulated sugar until the mixture looks smooth and a little glossy, about 1 minute. Whisk in the pumpkin puree and vanilla until everything is evenly combined.

Pour the dry ingredients into the wet and fold with a spatula just until the last dry streak disappears. Fold in the vegan chocolate chips and the pecans or pepitas, then stop mixing, because an overworked dough bakes up cakey.

Cover the bowl and chill the dough for 30 minutes. This firms up the pumpkin and keeps the cookies from spreading into flat disks in the oven.

Heat the oven to 350 F (175 C) and line two baking sheets with parchment paper. Scoop rounded 2-tablespoon portions of dough about 2 inches apart, then press each one down lightly with the back of a spoon.

Bake for 12 to 14 minutes, until the edges are set and the centers still look soft and slightly puffed. Let the cookies cool on the baking sheet for 5 minutes, then move them to a wire rack to cool completely.