To make the base, crush the cookies and place in a bowl.
Melt the butter and pour over the cookie crumbs. Mix until the crumbs resemble moist sand.
Press into the bottom of a 30cm tart tin/pie dish and place in the refrigerator.
To make the filling, combine the coconut milk, milk and coconut essence in a saucepan and place over gentle heat. Allow the mixture to get hot, but don't allow to boil.
In a separate bowl, combine the cornflour, egg yolks and caster sugar. When the coconut milk mixture is hot, slowly, and while whisking, add a ladle full to the cornflour mixture. Whisk until completely smooth then pour back into the pot with the remaining coconut milk.
Allow to heat gently while continuously stirring until thick and smooth. Allow to cook for at 7-10 minutes until the mixture is as thick as shop-bought custard and doesn't taste floury anymore.
Pour through a sieve and then into the chilled cookie crumb base.
Chill in the fridge for at least 2 hours.
When ready to serve, top with whipped cream and serve immediately.