Place mascarpone and low-carb sweetener in a deep bowl. Beat with an electric mixer on low for 2 minutes.
Add vanilla, pumpkin and pumpkin pie spice. Beat on low until incorporated.
Slowly, with the mixer running of low, add the heavy cream. Beat just until incorporated and fluffy, or for 2 minutes. Do not over beat.
Top with whipped cream (optional), chopped sugar-free chocolate and mint.