Blend the pandan leaves with the eggs, egg yolk, and coconut milk until smooth. Then, sift the mixture to remove those fibrous strands of pandan. If you're using pandan extract, ignore this step and just add the extract to the eggs and coconut milk and stir well.
Prepare a bain marie/water bath on medium heat (~80°C), pour the liquid into a bowl on the bain marie, and add the sugar and salt.
Now here’s where your patience will be tested. With a spatula, stir the mixture until it turns thick and custardy. This will take around 30 minutes, if not longer. At first, it may not look like much is happening, but keep stirring and scraping the bottom and sides of the bowl to make sure the egg doesn’t curdle, I promise you it'll thicken up with time!
When your kaya reaches a custard-like consistency, remove from the bain marie and let cool. If there are large lumps in the kaya, you can pass it through a sieve and give it a whisk, which should hopefully smoothen it out! If that doesn't work, you can blend it (add some water if it's too thick to blend, and then cook it further to get to the desired consistency).
Have on toast with a thick wad of butter for a truly Malaysian breakfast!