Place the oysters in a strainer set over a large bowl to catch the liquid.
In a medium saucepan, bring the stock and potatoes to a boil. Lower the heat and simmer for 8 minutes. Stir in the oyster liquid, cream, and saffron. Return to a boil. Lower the heat and simmer for 8 minutes.
Cut each oyster in half with kitchen scissors. Stir the oysters into the soup with the scallions