Preheat the oven to 190C/375F/Gas 5.

Line a 23 x 33 cm / 9 x 13 inch Swiss roll tin with non stick baking paper.

Wash the spinach and remove the stalks, then cook the wet leaves in a covered pan without extra water until just tender.

Drain the spinach well, squeeze out all the excess moisture and then chop finely.

Tip the spinach into a bowl, beat in the butter and egg yolks and season with salt, pepper and nutmeg.

Whisk the egg whites until stiff and fold into the spinach mixture.

Spread into the tin and sprinkle with half the cheese.

Bake for 10-12 minutes, until just firm.

Meanwhile, make the filling.

Melt the butter in a pan and fry the mushrooms until tender, stir in the flour and cook for 1 minute.

Gradually add the milk, then bring to the boil, stirring until thickened.

Simmer for a further 2-3 minutes.

Remove from the heat and stir in the cream and chives.

Remove the cooked roulade from the oven and turn out on to a sheet of non stick baking paper.

Peel off the lining paper and spread the roulade evenly with the mushroom filling.

Roll up the roulade fairly tightly and transfer to an ovenproof dish.

Sprinkle over the remaining cheese and return the roulade to the oven for about 4-5 minutes to melt the cheese.

Serve at once, cut into slices.