Preheat oven to 350°F (177°C). Spray a 12-count muffin pan with non-stick spray or line with cupcake liners. Set aside.

In a large bowl, toss the flour, baking powder, baking soda, salt, cinnamon, and pumpkin pie spice together until combined. Set aside. In a medium bowl, whisk the brown sugar and eggs together until combined. Whisk in the pumpkin, oil, milk, and vanilla until combined. Pour the wet ingredients into the dry ingredients and stir until just combined. Do NOT overmix the batter.

Spoon the batter into the prepared cupcake cups. Fill only about 1/2 – 2/3 full. If you have extra batter for 1-2 cupcakes, bake a 2nd batch. Bake for 17-18 minutes or until a toothpick inserted in the center comes out clean. Allow to cool completely before frosting.

In a medium bowl using a handheld or stand mixer fitted with a paddle attachment, beat the butter, marshmallow creme, vanilla, and cream on medium speed until completely smooth. Add 2 cups confectioners’ sugar and the salt slowly with the mixer running on low, then increase the speed to high and beat for 1 minute. If it looks too thin, add 1/4 cup more confectioners’ sugar. Frost cooled cupcakes however you’d like. I used a Wilton #12 piping tip.