Use a knife to gently cut the blood jelly into rectangular prisms. Go from top to bottom along the length and finish it with one line through the middle from left to right.
Run the knife along the box’s perimeter.
Fill a small pot with enough water to completely cover all the blood jelly and season it with 1/2 tsp salt.
Put the blood jelly in then turn the heat up to high without the pot lid.
Occasionally give the blood jelly a gentle stir to stop it from sticking to the pot’s base as the water begins to thicken.
When the water boils, turn the heat off and put the pot lid on. Let it sit for an hour on the stove to slowly cook further.
Store the cooked blood jelly before adding it into any soup by filling the plastic container it came in with cold water.
Empty the pot’s contents into a sink with cold tap water running.
Carefully transfer the blood jelly back into the box.
Wait until the dish it’s to be served with is close to ready. If it’s a soup, drain and add the cooked blood into the pot to absorb all the flavour.