Beat ¼ cup sugar, vanilla, and cream cheese with a mixer at medium speed until well mixed.
Beat whipping cream in a separate bowl at high speed until peaks form.
Gently fold whipped cream into cream cheese mixture.
Pipe mixture into fillo shells. Refrigerate during next steps.
In a small saucepan, combine 1 cup sugar, eggs, egg yolks, salt, and lemon juice over medium-high heat.
Whisk constantly until thick (about 3 minutes).
Remove from heat and add butter 1 cube at a time until melted. Cool.
Pour over cheesecake layer in shells. Refrigerate 1-2 hours and garnish as desired.