Preheat the oven to 350 degrees F (175 degrees C). Lightly grease baking sheets.
To make the cookie dough: Combine brown sugar and oil in a bowl. Mix in pumpkin and eggs, beating well. Add flour, cinnamon, ginger, cloves, salt, baking powder, baking soda, and vanilla together into a separate bowl. Fold dry ingredients into wet ingredients and mix to combine.
Drop dough by heaping teaspoons onto the prepared baking sheets.
Bake in the preheated oven until cookies spring back when lightly touched, 10 to 12 minutes . Cool on baking sheets briefly before transferring to wire racks to cool completely while you make the filling.
Make whoppie pie filling
Assemble once cookies are cool. Make sandwiches from two cookies filled with whoopie pie filling.
