Preheat oven to 350°F (175°C) and line a baking sheet with parchment paper.
Cream together softened butter and sugar in a large bowl until light and fluffy.
Add egg and vanilla extract to the butter mixture and mix until combined.
Whisk flour, baking powder, and salt in a separate bowl, then gradually add to wet ingredients to form dough.
Scoop dough into large 3-inch balls, flatten slightly on the baking sheet, and create an indent in the center of each cookie.
Bake for 10-12 minutes until edges are set, then let cookies cool completely.
In a saucepan over medium heat, whisk pumpkin puree, brown sugar, granulated sugar, and spices.
Stir in vanilla extract and heavy cream; cook for 2-3 minutes until thickened then remove from heat and let cool.
Spoon pumpkin filling into the center of each cooled cookie.
Chill cookies in the refrigerator for 15-20 minutes to set the filling.
Top each cookie with whipped cream and sprinkle with cinnamon before serving.