01 - Place softened cream cheese in a medium mixing bowl. Using a hand mixer on medium speed, beat until completely smooth and creamy, approximately 2 minutes.
02 - Add powdered erythritol and vanilla extract to the bowl. Continue beating on medium speed until fully incorporated and no sweetener granules remain visible.
03 - With the mixer running, slowly drizzle in the heavy whipping cream. Increase speed to high and continue beating until the mixture transforms into a light, airy mousse that holds soft peaks when the beaters are lifted. Fold in lemon zest at this stage if using.
04 - Divide the cheesecake fluff equally among four serving glasses, ramekins, or small bowls, using a rubber spatula to scrape the bowl clean.
05 - Top each portion with fresh berries and chopped nuts as desired. For optimal texture, refrigerate for at least 1 hour before serving. Keeps refrigerated for up to 2 days.