Start by preheating your oven to 350°F (177°C) and prepare a 12-count muffin pan with cupcake liners.

In a large bowl, whisk together flour, baking powder, baking soda, salt, cinnamon, and pumpkin pie spice. Set this mixture aside. In a separate bowl, combine the oil, eggs, brown sugar, pumpkin, and vanilla extract. Pour the wet ingredients into the dry mixture and stir or use a mixer until fully combined; the batter will be thick.

Carefully fill the cupcake liners, filling them only about 2/3 full to prevent overflow. Bake for 20-22 minutes, checking with a toothpick for doneness. Once done, allow the cupcakes to cool completely before moving on.

For the frosting, in a large bowl, use a handheld or stand mixer with a paddle or whisk attachment to beat together the cream cheese and butter until smooth and creamy. Add 3 cups of confectioners’ sugar, vanilla, and salt. Begin at low speed for 30 seconds, then switch to high speed for 2 minutes. If you desire thicker frosting, you can add the extra 1/4 cup of confectioners' sugar.

Once your cupcakes are cooled, frost them according to your preference. Enjoy your delicious treats!