In a large bowl, using an electric hand mixer, beat the cream cheese, pumpkin puree, 1 teaspoon pumpkin pie spice, vanilla, and brown sugar until it becomes smooth and creamy.
Gently fold in the whipped cream. Spoon the mousse into individual serving dishes, top each mousse with a dollop of whipped cream, if desired, and a sprinkling of the remaining 1/2 teaspoon pumpkin pie spice.
Cook's Note: Mousse can be made a 1 day in advance.
Recipe courtesy Sandra Lee