1. Add the heavy whipping cream, powdered sugar and vanilla extract to a large mixer bowl and whip on high speed until soft peaks form. If making the chocolate version, also add the cocoa.
2. Add the mascarpone cheese to the whipped cream and whip on medium speed until the cheese is well incorporated and not lumpy. Continue whipping until stiff peaks form, turning the speed up to medium-high, if needed. It will happen fairly quickly.

The mascarpone whipped cream will stay stable in the fridge for several days, even for a week, though it won’t remain as fresh. If you are going to use it to frosting something, I would suggest using it right away so that it maintains its texture well. Once it’s piped or spread, etc, it’ll stay put and nice and fluffy.