Fry the onions, fennel bulb, leeks and celery in the butter on gentle heat until soft but not coloured. Deglaze with the white wine.
Separately, deep fry the skate bones until they are golden in colour and become almost gelatinous. Drain and add the bones to the pot and continue to cook. Add the squid ink followed by the vegetable stock and simmer for 25 minutes. Strain the sauce and re