Ensure the cream cheese is fully softened. Remove the cream cheese from the refrigerator at least one hour before beginning the recipe. Gather and accurately measure all necessary ingredients. If using powdered sugar, sift it lightly to ensure maximum smoothness and prevent lumps.

Place the softened cream cheese and the sifted powdered sugar into the bowl of a stand mixer fitted with a paddle attachment, or use a large mixing bowl with an electric hand mixer.

Beat the cream cheese and sugar mixture on medium speed for 2 to 3 minutes, or until the mixture is light, creamy, and completely smooth. Stop the mixer midway through the process to scrape down the sides of the bowl thoroughly.

Reduce the mixer speed to low. Add the entire jar of marshmallow fluff, the vanilla extract, and the fresh lemon juice (if using). Mix slowly until the ingredients are just combined.

Increase the mixer speed to medium-high. Continue beating the mixture for 3 to 4 minutes. The goal is to whip air into the dip, making it light, fluffy, and voluminous. Stop the mixer occasionally to scrape down the sides and the bottom of the bowl, ensuring no sticky, heavy marshmallow remains unmixed.

Once the dip is exceptionally smooth and aerated, transfer it immediately into an airtight container. Place the dip in the refrigerator to chill for a minimum of 2 hours. Chilling is essential to allow the dip to firm up and for the flavors to fully meld.

Just before serving, remove the fruit dip from the refrigerator. If it is too stiff, allow it to sit out on the counter for 10 to 15 minutes to soften slightly. Transfer the dip into an attractive serving bowl or shallow platter.

Arrange the prepared fresh fruit and other dippers (graham crackers, cookies) around the bowl on the serving tray. Serve immediately. This dip is best consumed within 2 hours of being served at room temperature.