The first step, take the appropriate amount of grapefruit peel and wash it, then use scissors to cut the grapefruit peel into small pieces into a pot, and then add the appropriate amount of water to boil over high heat.
The second step, after boiling, cook with low heat for 15-20 minutes, then squeeze out the water from the grapefruit peel and discard it.
Step 3, add rock sugar to the rest of the soup, then pour into a bowl and let it cool to drink.