Nervetti salad

• 500 g beef nervetti (tendons and cartilage from beef shin)
• 1 red Tropea onion
• 1

Fill a deep pot with 4 litres water, 100 ml vinegar and a pinch of salt. Bring to a boil, then add the beef tendons. Return to the boil, lower the heat, place the lid covering three-quarters of the pot and cook for 4 hours.

Once ready, drain well and place tendons in a bowl, pressing them d