This is my favourite lasagne dish, which I sometimes make on my birthday, as it takes advantage of the summer pea crop. It serves 10-12 people, so is ideal for a big dinner party.
Pre-heat the oven to 200°C/400°F/Gas mark 6. Chop and cook the spinach without water over a very low flame for about 5 minutes. Drain and reserve the liquid for the cheese sauce. Boil the peas and steam the courgettes/zucchini above them. Add the courgettes/zucchini to the spinach. Ble