Gather all ingredients and preheat oven to 350 degrees F (175 degrees C).

To make the pastry dough: Cream 12 ounces of cream cheese, 1 pound of butter, and sugar together in a large bowl until thoroughly blended. Mix in flour, a little at a time, until dough is workable.

Cut dough into 4 equal-sized pieces; roll the pieces into balls and refrigerate until needed.

To make the filling: Mash 12 ounces of cream cheese with brown sugar, pumpkin pie spice, cinnamon, and salt in a bowl until smooth and well combined; beat in eggs, one at a time, incorporating each egg before adding the next one. Mix in the pumpkin, evaporated milk, and vanilla extract until filling is smooth.

Cut each dough ball in half, and cut each half into 12 pieces (96 total pieces).

Working in batches, press each small piece of dough into the bottom and up the sides of mini muffin cups. Fill mini crusts almost to the top with the pumpkin filling. Refrigerate unused dough until you need it to make the next batch.

Bake in the preheated oven until the filling is set and the crusts are lightly golden brown, 25 to 30 minutes. Allow to cool completely before frosting.

Mash 1/2 cup of butter, shortening, and 8 ounces of cream cheese together in a bowl until thoroughly combined; mix in confectioners' sugar and marshmallow creme until smooth and creamy.

Spread or pipe the frosting onto the cooled tarts. Sprinkle each tart with a few chopped pecans. Refrigerate until serving.