1 medium cauliflower, leaves removed and thinly sliced
50g/1¾oz baby spinach
4 medium waxy potatoes, peeled and grated
600g/1lb 5oz cold mashed potato
salt and freshly ground black pepper
100g/3½oz â00â flour, plus extra for rolling out
salt
30g/1oz unsalted butter
100g/3½oz strong hard cheese, grated
150ml/¼ pint double cream
1 free-range egg, beaten
150ml/¼ pint whole milk