Prepare the Lemon Curd (Optional):

1. In a small saucepan, whisk together the lemon juice, sugar, and egg yolks over medium heat.
2. Add the butter and lemon zest, cooking while stirring constantly until the mixture thickens (about 5-7 minutes).
3. Remove from heat and strain the lemon curd through a fine-mesh sieve to remove any lumps.
4. Let the lemon curd cool completely before using.

Make the Lemon Cheesecake Mousse:

1. In a large bowl, beat the softened cream cheese and granulated sugar until smooth and creamy.
2. Add the vanilla extract, lemon zest, and lemon juice, continuing to beat until well combined.
3. In a separate bowl, whip the chilled heavy cream and powdered sugar until soft peaks form.
4. Gently fold the whipped cream into the cream cheese mixture to create a light and fluffy mousse.
5. Spoon or pipe the mousse into serving glasses, leaving room for the garnish.

Add the Lemon Curd and Assemble:

1. If using lemon curd, spoon a layer of the curd into the mousse or swirl it through the layers for added flavor.
2. Alternatively, drizzle the lemon curd on top for a finishing touch.

Garnish and Serve:

1. Top the mousse with fresh blueberries, a slice of lemon, and crumbled graham crackers or cookies for added texture.
2. Garnish with a sprig of mint for a pop of color.

Chill and Enjoy:

1. Refrigerate the mousse for at least 1 hour before serving to allow the flavors to meld and the mousse to set.
2. Serve chilled and enjoy this light and tangy Lemon Cheesecake Mousse!