Preheat the oven to 190°C, gas mark 5. Roll out the pastry and line a 20cm, ovenproof tart dish. Put back in the fridge. Keep the pastry trimmings.
Melt the butter in a frying pan over a medium heat and fry the onion until soft.
Add the ham and fry for a few minutes more. Scatter the ham and onions in the pastry case.
Beat 2 eggs with the cream, season and pour over the ham and onions. Scatter on the parsley. Carefully break an egg into a cup, then tip into the tart. Repeat with the other 3 eggs. Cut leaves from the pastry trimmings, brush the tart rim with water and press on the leaves. Bake for 30-35 minutes. Serve warm or cold with salad.
This recipe was first published on Waitrose.com in December 2004.