Preheat oven to 350°F. Line a baking sheet with parchment paper.In a medium bowl with an electric hand mixer, combine sugar, salt, pumpkin pie spice, egg, pumpkin, vanilla, and evaporated milk. Beat until well combined and smooth.Line mini tart shells on prepared baking sheet. Using a small cookie scoop (2 teaspoons), fill each mini tart shell with pumpkin pie fillingCarefully transfer pan to preheated oven and bake for 15-17 minutes or until shells are golden and the filling appears to be set. Carefully remove mini pumpkin pies to a cooling rack.If desired, top with freshly whipped cream or Cool Whip.