Put eggs in a pan of just simmering water and cook for 5-6 minutes for lightly cooked and 10 minutes for hard-boiled.
When cooked, drain and place in cold water until cooled. Carefully peel and leave in cold water until needed. Slice the potatoes; grill the Parma ham for 2 minutes, until crunchy.
To make a basic vinaigrette simply mix 3tbsp of white wine vinegar with 150ml of vegetable oil. Add 1tbsp of wholegrain mustard and whisk well to combine. Add the crushed garlic and seasoning.
Toss the watercress leaves with the dressing and potatoes. Place on a serving plate, cut the eggs in half and add to the salad, then crumble the cooked Parma ham over the top.
For the vinaigrette, add a pinch of dried chilli flakes for an extra kick or freshly chopped parsley for a fresh taste.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.