01 - Place softened cream cheese in a medium mixing bowl. Using a hand mixer, beat on medium speed until completely smooth and creamy with no lumps remaining.
02 - Add powdered erythritol and vanilla extract to the bowl. Continue beating on medium speed until the sweetener is fully dissolved and the mixture is uniform.
03 - Mix in the lemon zest if using, distributing evenly throughout the cream cheese mixture.
04 - With the mixer running on low speed, gradually pour in the heavy whipping cream. Increase speed to medium-high and continue beating until the mixture becomes light, airy, and holds soft peaks when the beaters are lifted.
05 - Divide the cheesecake fluff evenly among four serving glasses or dessert bowls, using a rubber spatula to scrape the bowl clean.
06 - Top each portion with fresh berries and chopped nuts if desired. Serve immediately for a fluffy texture, or refrigerate for up to 2 days for a firmer, colder consistency.