Preheat your oven to 350°F (175°C) and grease your Twinkie pan.

In a large mixing bowl, combine the spice cake mix and pumpkin puree until thoroughly blended.

Spoon the Pumpkin Spice Twinkie batter into the prepared molds, filling each about two-thirds full.

Place the filled Twinkie pan in your preheated oven and bake for 15 to 18 minutes, until a toothpick inserted comes out clean.

Allow the Twinkies to cool in the pan for about 5 minutes before transferring them to a wire rack.

While your Twinkies cool, prepare the marshmallow filling by beating together the marshmallow cream, shortening, salt, and powdered sugar until light and fluffy.

Transfer the filling into a piping bag and snip off a small tip for filling.

Using a chopstick, poke three holes in the bottom of each cooled Twinkie for the filling.

Fill each hole with the creamy marshmallow filling using the piping bag until you see the filling bulge slightly.

Serve your Pumpkin Spice Twinkies on a platter, optionally pairing with vanilla ice cream or whipped cream.