Day 1

• Sauté the sliced onion with a pinch of salt, olive oil and 1 tbsp butter over a low heat for 10 minutes until translucent.
  
• Add the garlic cloves, rosemary and crushed peppercorns, stir to combine and cook for another 5 minutes. When the onions and garlic are soft enough remove from the stove to cool.
  
• While the onions are slowly cooking, prepare the veal shank. Use a sharp knife to remove all white membrane and tie up the veal shank with kitchen twine.
  
• Place the veal shank in the sous-vide pouch with the cold onion confit and seal the bag.
  
• Program the precision water bath cooker to 75°C, submerge the bag into the water and cook for 18 hours.
  

Day 2

Prepare the sauce

• Open the bag, remove the veal and refrigerate.
• Sieve the jus from the bag and discard the onions.
• Stir fry the chopped onion in olive oil for 3-4 minutes. Add the red wine vinegar and boil to reduce ¾.
  
• Add the demi-glace and cook for 10 minutes. Monter the sauce au beurre, add the parsley and season to taste.
• Slice the veal shank into medallions and pan fry with a tbsp of butter until brown on both sides; add the onion jus and simmer for 5 minutes.
  
• Arrange the onion sauce on the bottom of the plate and the veal shank medallions with the fresh gremolata on top or serve with a garnish of vegetables.