Preheat your oven to 425°F.
Grease the muffin tin with nonstick spray.
Lightly flour the surface you're going to use for cutting out the crust circles. Flour the rim of the cutter as well.
Using a 4" diameter circle glass, or cookie cutter, cut out the pie crust circles.
You will have leftover pie crust that you will need to roll out for the rest of your pies. Combine the leftover dough into a ball. Using a rolling pin, roll it out to the same thickness as the initial dough sheet.
Cut out the remaining crusts using the 4-inch cutter.
Press pie crust circles into the muffin tin wells.
In a large bowl, using a hand mixer, combine the pumpkin, milk, eggs, and spice until creamy.
Pour mixture into each pie crust about ¾ of the way-a little more is ok just as long as you are not meeting the top of the crust.
Place mini pumpkin pies in the oven at 425°F for 15 minutes.
Reduce the oven heat to 350°F. and bake another 20 minutes.
Allow pies to fully cool before optionally topping them.