Cut off the lid of the kabocha squash and scoop out all the seeds. Rinse the insides and let it dry upside down on a towel for about 15 minutes.

In a medium pot, add the chopped palm sugar and most of the coconut milk (reserve about 2 tablespoons). Add the pandan leaf, folding it in half and tying it in a knot. Cook over medium-low heat until the sugar dissolves, about 5-7 minutes.

In a small bowl, combine the reserved coconut milk with the rice flour and stir until smooth.

In a large mixing bowl, whisk together the eggs, egg yolk, the dissolved rice flour mixture, and salt until fully combined.

Slowly whisk the warm palm sugar mixture into the egg mixture, tempering to prevent curdling. Strain the mixture through a fine-mesh sieve into a spouted container.

Preheat your steamer (or oven) while filling the kabocha squash. Place the squash in a casserole dish and pour the custard into it, leaving an inch of space at the top.

If steaming, cover with the lid and steam for 40-60 minutes or until the custard is just set (about 170°F).

If baking, preheat the oven to 320°F, place squash in a larger baking dish filled with water, and bake for 60-70 minutes, checking for doneness.

Once set, let it cool completely before slicing. Cut the pumpkin into wedges to showcase the custard.