In a stand mixer or a large bowl, cream together the softened vegan butter, pumpkin puree, brown sugar, granulated sugar, and vanilla until you have a light and fluffy mixture.

In another large bowl, whisk together the flour, baking powder, pumpkin pie spice, cornstarch, and salt.

Gradually add the dry mixture into the wet ingredients, mixing on low speed until just combined. Don't over-mix!

Cover the bowl and chill the dough in the fridge for 30 minutes or overnight.

Preheat your oven to 350°F (177°C).

Using a medium cookie scooper or a large spoon, scoop out 2-inch balls of dough. Flatten them into disks and place them a couple of inches apart on the parchment-lined baking sheet.

Bake on the center rack for about 10-12 minutes and allow cooling completely on the baking sheet.

In a medium bowl, whip together all the frosting ingredients using an electric mixer until combined.

Spoon the frosting into a piping bag fitted with the Wilton Piping Tip #2A. Pipe a swirl of cinnamon frosting on each cooled cookie and sprinkle pumpkin pie spice on top.