In a medium saucepan, whisk together the egg yolks and sugar until well blended.
Whisk in milk and cook over medium.
Stir constantly until boiling.
Boil gently for 1 minute.
Remove from heat.
Transfer to a glass bowl.
Cool slightly.
Cover tightly (wrap going down on the custard mixture) and chill for 1 hour.
In a different bowl, beat cream and vanilla until stiff peaks form.
Pull custard out of fridge and whisk mascarpone into yolk mixture until smooth.
Put Raspberry Torani syrup in a small bowl.
Dip each ladyfinger into the raspberry syrup until soaked.
Arrange half of the lady fingers on the bottom of a 9×13 pan.
Spread half of the raspberry curd.
Spread half of the mascarpone mixture.
Spread half of the lemon curd.
Spread half of the whipped cream.
Repeat layers.
Cover and refrigerate overnight.
Before serving, sprinkle with Xylitol sweetener and fresh raspberries (if desired).