Preheat the oven to 350°F (175°C) and line two baking sheets with parchment paper.

In a large bowl, cream together the vegan butter, brown sugar, and granulated sugar until light and fluffy.

Mix in the pumpkin puree and vanilla extract until smooth.

In a separate bowl, whisk together the flour, baking powder, baking soda, pumpkin pie spice, cinnamon, and salt.

Add the dry ingredients to the wet ingredients and stir until just combined. If the dough seems too dry, mix in the non-dairy milk, 1 tablespoon at a time.

Fold in the optional white chocolate chips or pecans if using.

Scoop tablespoon-sized portions of dough onto the prepared baking sheets, spacing them about 2 inches apart. Slightly flatten each mound with your fingers or the back of a spoon.

Bake for 11 to 13 minutes, or until the edges are set and the centers look slightly soft.

Let the cookies cool on the baking sheet for 5 minutes, then transfer to a wire rack to cool completely.