1.   Place onion mixture over potatoes in pan and add oysters with cup oyster liquor.

2.   Simmer oysters in oyster liquor until oyster edges curl.

3.   Add enough of the oyster liquor to moisten.

4.   Add oyster liquor, seafood stock and tomatoes and bring to a simmer.

5.   What is left is a pale yellow juice, as thin as water, as concentrated and saline as oyster liquor.