Preheat oven to 350°F and line a baking sheet with parchment paper.
In a large bowl, cream together the butter, cream cheese, granulated sugar, and brown sugar until smooth and fluffy. Mix in the egg and vanilla extract until fully combined.
In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and optional cinnamon. Gradually mix the dry ingredients into the wet ingredients until a soft dough forms.
Chill the dough for 20–30 minutes to prevent spreading.
Scoop large dough balls and flatten into thick discs. Press a deep well into the center of each cookie, leaving a raised edge around the outside.
In a bowl, whisk together the pumpkin puree, brown sugar, egg yolk, heavy cream, vanilla, pumpkin pie spice, cinnamon, cornstarch, and flour until smooth.
Spoon about 1 tablespoon of filling into the center of each cookie.
Bake for 13–16 minutes, until the edges are set and the centers have a slight jiggle but are no longer liquid.
Allow cookies to cool on the baking sheet for 15 minutes, then transfer to the refrigerator and chill for at least 1 hour to fully set the filling.
In a separate bowl, beat the heavy cream, powdered sugar, and vanilla until soft peaks form.
Top each chilled cookie with whipped cream before serving.