Peel the brown skin off the back of the coconuts and grate the coconut meat using a hand grater or blender.

Add some of the water to the grated coconut and blend or mix well.

Strain the mixture through a cheesecloth or fine-mesh sieve, squeezing to extract the coconut milk.

In a small bowl, blend the custard powder or cornstarch with 2 tablespoons of water to create a smooth paste.

Bring 1/2 cup of water to a boil in a saucepan.

Add the custard paste to the boiling water, stirring constantly to prevent lumps.

Continue to boil the mixture, stirring constantly, until the color darkens slightly.

Remove the saucepan from the heat and let it cool slightly.

Add the coconut milk to the cooled custard mixture and sieve the custard to remove any lumps.

Add the condensed milk and evaporated milk to the coconut milk mixture.

Add the almond essence to taste.

Pour the mixture into a freezer-safe container.

Freeze for at least 2-3 hours, or until solid.

For a creamier texture, churn the ice cream in an ice cream maker according to the manufacturer's instructions.