• Preheat oven to 350°F and line 2 baking sheets with parchment paper.
• In a medium-sized bowl, sift together the flour, baking powder, baking soda, salt, and pumpkin pie spice.
  1½ cups all-purpose flour, 1 teaspoon baking powder, 1 teaspoon baking soda, 1 teaspoon salt, 2 tablespoon pumpkin pie spice
• In a large bowl, mix together the pumpkin purée, brown sugar, egg, and vanilla extract. Whisk and stir until completely combined.
  1 15 oz can pumpkin purée, 1⅓ cup brown sugar, 1 large egg, 1 teaspoon vanilla extract
• Working in batches, stir in the flour mixture. Keep adding and stirring until just combined.
• Use a medium ice scoop or a large spoon to add about 1½ to 2 tablespoons of the batter onto the parchment paper. Use a spoon to spread the dough to about a 2-inch diameter. Continue with the remaining batter, leaving about 1 inch between each round of batter.
• Bake for 15 minutes, switching the baking sheets halfway through.
• Remove the baking pans from the oven and let the cookies cool for about 10 minutes. Carefully peel the cookies away from the parchment paper and allow them to cool on racks completely, about another 10 to 15 minutes.

Make the Filling and Assemble the Whoopie Pies

• While the cookies are cooling, make the filling by adding the softened butter and cream cheese to a large mixing bowl. Use a hand mixer (electric works well) to cream the butter together with the cream cheese until smooth and fluffy. Add the confectioners' sugar and vanilla extract. Mix on low, gradually increasing the speed until fully combined.
  4 tablespoon unsalted butter, 4 oz cream cheese, 1 cup confectioners' sugar, 1 teaspoon vanilla extract
• Turn half of the cookies over and pipe in the cream cheese filling, or spread with a spoon and/or spatula. Top with the remaining cookies.