Make the Pumpkin Spice Cookies:
Preheat your oven to 350°F (175°C) and line two baking sheets with parchment paper.
In a medium bowl, whisk together the flour, baking powder, baking soda, cinnamon, nutmeg, ginger, cloves, and salt.
In a large bowl, cream together the butter and brown sugar using an electric mixer until light and fluffy.
Add the egg and vanilla extract, beating until combined.
Mix in the pumpkin puree.
Gradually add the dry ingredients to the wet ingredients, alternating with the milk, mixing until just combined.
Using a cookie scoop or tablespoon, drop dollops of batter onto the prepared baking sheets, spacing them about 2 inches apart.
Bake for 10-12 minutes, or until the tops spring back when lightly touched.
Let the cookies cool on the baking sheets for 5 minutes before transferring them to a wire rack to cool completely.
Make the Cream Cheese Filling:
In a large bowl, beat the cream cheese and butter together until smooth and creamy.
Gradually add the powdered sugar, one cup at a time, mixing well after each addition.
Stir in the vanilla extract and optional ground cinnamon.
Beat until the filling is smooth and fluffy.
Assemble the Whoopie Pies:
Pair up the cookies by size and shape.
Spread or pipe a generous amount of cream cheese filling onto the flat side of one cookie.
Gently press the flat side of a second cookie on top to form a sandwich.
Repeat with the remaining cookies and filling.