01 - Place softened cream cheese in a medium mixing bowl. Using a hand mixer on medium speed, beat until completely smooth and creamy, approximately 1-2 minutes. Ensure no lumps remain.
02 - Add powdered erythritol and vanilla extract to the cream cheese. Continue beating on medium speed until fully incorporated and mixture appears glossy, about 30 seconds.
03 - With mixer running on low speed, gradually pour in heavy whipping cream. Increase speed to medium-high and continue beating until mixture becomes light, airy, and holds soft peaks when beaters are lifted, 2-3 minutes. Fold in lemon zest if using.
04 - Divide cheesecake fluff evenly among four serving glasses or bowls. Top with fresh berries and chopped nuts if desired. Serve immediately for fluffiest texture or refrigerate up to 48 hours for a firmer, mousse-like consistency.