Combine lemon juice, sugar, and eggs in a saucepan and whisk until smooth
Add butter and cook over low-medium heat, stirring constantly until the mixture thickens
Strain the lemon curd into a heatproof bowl, cover with cling wrap touching the surface, and chill completely
Blend graham crackers into fine crumbs and mix with softened butter
Reserve one tablespoon of crumbs for garnish
Beat cream cheese and sugar until smooth and creamy
Add chilled lemon curd and mix until fully combined
Add heavy cream and beat until thick and fluffy
Divide crumb mixture among 20 mini dessert cups and press gently into the base
Pipe a layer of cheesecake mousse over the crumbs
Pipe a layer of lemon curd over the mousse
Pipe the remaining mousse on top using a decorative tip if desired
Sprinkle reserved crumbs over the top
Refrigerate for at least 4 hours or until set before serving