Pickled red onion potato salad recipe

Ingredients

• 1.5kg potatoes (rooster are good), peeled and chopped into chunks
• 1 large red onion, sliced
• 5 tbsp red wine vinegar
• 1 tbsp caster sugar
• 2 good pinches sea salt
• 200ml mayonnaise
• 2 tbsp Dijon mustard (see tip)
• 2 gherkins, finely chopped
• 2 celery sticks, finely chopped
• Small bunch fresh chives, snipped
• 4 free-range eggs, boiled for 8 minutes, chopped into chunks