Preheat your oven to 425°F (220°C).

In a large mixing bowl, combine the pumpkin purée, sweetened condensed milk, egg, pumpkin pie spice, cinnamon, and salt. Mix until smooth.

Roll out your pie sheets on a floured surface until about 1/8 inch thick. Cut out circular shapes slightly larger than the muffin tin holes and press into the tin.

Scoop the pumpkin filling into each pastry shell, filling them just to the top.

Bake at 425°F for 15 minutes, then reduce to 350°F (175°C) and bake for another 15 minutes.

Roll out any leftover dough and cut out ghost shapes. Brush with melted butter and sprinkle with cinnamon sugar. Bake at 450°F for 6 to 8 minutes.

Let the tarts cool slightly and place the ghost decorations on top before serving.