Method,
Whisk cream, sugar, egg yolk and cornflour till smooth.
Stir over medium-low heat till thick enough to coat pot thinly.
Place pot in the waster bath, add vanilla extract.
Stir till mixture is half cool. leave to cool completely then pour into the tarts.
Preheat oven to 250 degree C, bake till the tarts turns brown, it takes abt 40 mins or so, depend on individual oven. Mine takes 50 mins.
Remove tarts from oven to wire rack, leave it to cool.
Serve within a few hrs while pastry is crispy.
Hope you enkoy!

recipe link ;