Wash and dry the chicory and cut off the stalks. Cut the chicory into strips about 1 cm (1/2 in) wide and the ham into 5-mm/J-in wide strips.

Heat the oil in a frying pan, add and fry the chicory and ham, season with salt and pepper and keep to one side.

Melt 50 g (2 oz) of the butter in a saucepan, add and cook the flour until golden. Stir in the milk a little at a time and simmer for 5 minutes, stirring continuously. Stir in the wine. Add the cheese in small pieces and stir until melted. Remove the sauce from the heat and stir in the beaten egg yolks.

Grease an ovenproof dish with butter and fill with the ham and chicory mixture. Cover with the cheese sauce, sprinkle with the breadcrumbs and parsley and dot with the butter.

Bake in a moderately hot oven (200°C, 400°F, gas 6) for 25 minutes.