Cut the top of the squash out and remove the seeds.
Rinse the inside of the squash and leave it to dry upside down.
Break the eggs and whisk the egg yolks and whites together in a large bowl.
Add brown sugar, salt, and pandan powder to the egg mixture and whisk everything together.
Add coconut milk to the egg mixture and whisk everything together until achieving a uniform consistency.
Drain the custard mixture through a sieve.
Pour the custard mixture inside the squash.
Place the squash onto the rack of a steamer pot with water with the stove set to high heat and cover with a lid. Reduce to medium heat once the water boils.
Steam the squash for at least 40 minutes, or until the top of the custard mixture solidifies, and use a sharp knife to see if the pumpkin is cooked.
Remove the steamed pumpkin from the steamer and let it cool.