One small (5.5 oz) can of coconut milk.
A similar amount of milk.
1/2 cup of tapioca pearls.
1/4 cup of crystallized coconut palm sap, or other form of palm sugar; or you could use a bit less of regular sugar, or even some maple syrup. (And honestly, given how sweet the dish came out, you could probably cut the sugar by 10-15% relative to this, as long as you're using palmyras in syrup, not packed in just water or some kind of juice.)
a pinch of salt (maybe 1/4 tsp?)
Simmer for five minutes. Add one mango, diced, and maybe half a cup of palm seeds. (We found them jarred, in syrup, at our local Asian grocer. I generally expect stuff in glass jars to taste fresher than stuff in cans, but it probably doesn't make a huge difference.)
Simmer for another five minutes. Test the a pearl to see if it's cooked through.
Cooking time may need adjustment depending on exactly what size / type of pearls you use.
Xta remarks that she should've taken a photo; it's not particularly pretty, but it is quite tasty. I was attempting to replicate a dessert I had once, a number of years ago, at a South-Chinese place in Mountain View. I think I came reasonably close, actually, on the first try.