Prepare the custard base:
In a saucepan, whisk together the eggs, sugar, and cornstarch until smooth.
Gradually add the milk while whisking to avoid lumps.
Cook the cream:
Place the saucepan over medium heat and cook, stirring constantly, until the mixture thickens into a custard.
Remove from heat and allow to cool slightly.
Add mascarpone and lemon:
Once the cream is warm (not hot), stir in the mascarpone and lemon zest. Mix until smooth and creamy.
Chill:
Cover with plastic wrap (pressed against the surface to prevent a skin from forming) and refrigerate for at least 2 hours.
Assemble the tart:
Spread the cream filling into a prepared tart shell or sponge base.
Decorate with fresh berries, lemon slices, or mint leaves for a beautiful finish.
Serving and Storage Tips
