I use an immersion blender (with the whip attachment) to mix small batches of frosting like this, but any mixer will work, or you can whisk it by hand if necessary, it's often hard to whip a small batch with a big stand mixer, a hand held mixer will work better.

First whip the heavy cream with powdered sugar until it whipped fluffy and thick and a soft peak forms when the whisk is pulled out of the cream.

Then add in the pieces of cream cheese and vanilla and mix until it's smooth.