Preheat your oven to 350°F.
On a surface dusted with flour, roll the pie crusts to approximately 1/8-inch thick.
Use a 3 1/2-inch round cookie cutter to cut circles from the dough. You should yield about 12 circles in total.
Grease a 12-cup muffin tin. Press each dough circle into a muffin cup, shaping it to fit.
In a medium bowl, whisk together the pumpkin purée, brown sugar, egg, evaporated milk, pumpkin pie spice, and salt until smooth.
Carefully spoon the pumpkin filling evenly into each crust, filling them about three-quarters full.
Bake the mini pies in the oven for 25 minutes, or until the filling is set and the crusts are golden brown.
Let the mini pies cool in the baking tin for 10 minutes. Next, gently take them out and set them on a wire rack to cool fully.
Serve the pies at room temperature or chilled. Top with whipped cream if desired.