Blanch the oxtail and scrape off the froth.
Pre-heat the oven at 180°C and roast all the bulbs as well as all the aromatic ingredients in the oven at 180°C for 8 minutes.
Put the blanched ox-tail and the roasted vegetables into the vacuum pack.
Season the pack as needed and vacuum the ox-tail tightly. Cook in a water bath for about 60°C for 10 Hrs.
Check the tenderness. Tear the packet off.
Serve it by using a skewer.