Cantonese red bean sweet soup

Rinse the red beans and soak 12 to 24 hours.

Strain the soaked beans and freeze them; the water inside expands as ice and shortens the cooking time.

Thaw the frozen beans in hot water.

Soak the aged tangerine peel in cool water half an hour, scrape the white pith off with a paring knife so it does not turn the soup bitter, then mince it fine.

Bring five cups of water with the tangerine peel to a boil, add the beans, return to a boil, drop to medium-low, crack the lid to stop it overflowing and cook one hour.

Kill the heat, lift out about 80 per cent of the beans in a mesh strainer and mash them with a spoon, rinsing the mash back through with the cooking liquid until only shells are left; discard the shells.

Return to medium-low and simmer another half hour until obviously thickened.

Stir in 20 to 30 g of rock sugar until dissolved.