In a medium bowl, combine the butter, shortening, flour, and salt. Blend the butter and shortening into the flour using your fingertips.

When the fats are evenly distributed, sprinkle the cold water on top and stir the dough together with a fork.

Bring the dough together into a ball, press it into a disk, then wrap and refrigerate for 20 minutes.

Preheat the oven to 400°F.

Stir together all filling ingredients with a whisk. Set aside.

Remove the dough from the fridge and flour a work surface. Roll the dough out to a rough 9" circle.

Use a 4" round cookie cutter to cut out 10 round pieces of dough.

Fit one dough circle into each cup in the muffin pan and gently push it into the cup.

Divide the pumpkin filling mixture between the cups.

Bake for 10 minutes, then turn the oven down to 325° for another 10 minutes.

Let mini pies cool in the pan completely before removing. Run a knife around the edges to pop them out.