7. Prepare the Limoncello Mascarpone Cream:

In a mixing bowl, whisk together the mascarpone cheese, heavy cream, Limoncello, powdered sugar, lemon zest, and vanilla extract. Start at a low speed and gradually increase to medium-high until the mixture becomes smooth and thick, forming soft peaks.
Adjust the sweetness with more powdered sugar or Limoncello if desired.
8. Assemble the Cake:

Once the cake has cooled completely, spread a generous amount of the Limoncello mascarpone cream over the top of the cake.
Garnish with chopped pistachios, fresh lemon zest, and a few fresh mint leaves for a beautiful presentation.
9. Serve:

Slice and serve the cake chilled or at room temperature. The combination of the nutty pistachio and polenta cake with the refreshing Limoncello mascarpone cream is sure to be a hit.