In a small sauce pot, mix together the coconut milk and 1/2 cup sugar. Stir in the pandan leaves and salt and bring to a boil over high heat, keeping the pandan submerged in the milk as the leaves cook and soften. When the milk has come to a boil, remove from heat and let the mixture steep for 10 minutes.
Remove the pandan leaves from the milk, squeezing any excess liquid from the leaves into the milk. Discard the leaves.
In a medium stainless steel mixing bowl, whisk together the eggs, yolks and remaining 1/2 cup sugar. Whisk in the coconut milk mixture to form a custard base.
Place the stainless steel bowl over a medium pot of lightly simmering water. Gently cook the custard, stirring constantly with a rubber spatula, until the mixture thickens, 15 to 20 minutes. The final texture should have a thick custard consistency (a trail of the spatula should remain on the surface of the custard for more than 10 seconds).
Immediately remove from the heat and strain into a medium bowl set over a larger bowl of ice water. Stir until the custard cools, then cover and refrigerate until needed. This makes about 2 cups coconut jam, more than is needed for the remainder of the recipe. The jam will keep for 1 week, refrigerated.
Spread 2 tablespoons coconut jam evenly over both slices of the bread on the untoasted side. Then place a layer of shaved butter over the jam. Place one slice of bread over the other to form a sandwich.
Halve the sandwich, and then cut each half into thirds to form 6 even wedges.
To soft boil the egg, add the egg to boiling water. Cook for 6 minutes, remove and ice.
Pour the dark soy sauce over the egg and dash with the pepper. Serve the egg alongside the sandwich wedges.