Preheat oven 200C/400F/Gas 6. Butter a shallow ovenproof dish.
Add 600ml/1 pint water into a pan with the onion and apricots. Bring to the boil, then reduce the heat and simmer for about five minutes. Drain.
Put the breadcrumbs into a large bowl. Melt the butter in a frying pan and pour half of this onto the breadcrumbs.
In the remaining butter, fry the chestnuts over a high heat until lightly browned. Tip into the bowl with the breadcrumbs. Add the apricots, onion and parsley to the bowl. Season with salt and pepper.
Turn into a buttered, shallow ovenproof dish and bake in a preheated oven for about 25-30 minutes until crisp and hot right through.
To freeze: cool and cover the dish with foil, freeze until Christmas Eve.
To thaw: take out the night before using and thaw overnight. Crisp in a hot oven (as above) for about 10-15 minutes.