Preheat the oven to 160°C (325°F), gas mark 3.
Boil the 4 eggs in a large saucepan of water for 5 minutes and then immediately plunge them into a bowl of iced water to stop them from cooking further.
Carefully peel the eggs.
Put the flour, beaten eggs and breadcrumbs in 3 separate shallow bowls.
Coat the boiled eggs in flour, dip in the beaten egg and finally roll in the breadcrumbs to coat.
Transfer to the fridge for 15 minutes and then dip each egg in the beaten egg and roll in the breadcrumbs to give them a second coating.
Meanwhile, divide the pancetta between two non-stick baking trays, transfer to the oven and cook for 20 minutes until crisp.
Drain on kitchen paper and set aside.
Heat the oil to 180°C (350°F) ready for deep-frying.
Carefully lower the eggs into the hot oil and fry for 2-3 minutes until golden brown and crisp. Remove from the oil and drain on kitchen paper.
For the salad, combine the shallot, oil, vinegar, mustard and tarragon in a bowl and season to taste.
Separate the yellow endive leaves and drop them into a bowl of iced water to crisp.
Drain the leaves on kitchen paper and then toss with the apple and some of the shallot vinaigrette.
Divide the salad between serving plates and finish with crispy pancetta.
Serve with a crispy egg and a drizzle more of the vinaigrette.