Rinse and soak the glutinous sticky rice in water overnight.
Brew the Hong Kong milk tea and chill in the fridge.
Cook the rice:
Add the drained sticky rice to a shallow dish.
Bring a pot of water up to a boil and place the dish with the sticky rice in.
Cover with a lid and steam for 20 minutes, or until the rice is cooked.
Combine:
Remove the rice and while still hot, pour in the Hong Kong milk tea, whole milk, evaporated milk, sweetened condensed milk (or sugar) and heavy cream (if using).
Gently combine the rice with the milk tea mixture and let it absorb. If it's too thick, add a little more whole milk to loosen.