For the roll:

• 1 lb (450 g) spinach
• 4 free-range eggs, separated
• Salt and pepper
• Grated nutmeg

For the filling:

• 2 tablespoons olive oil
• 1 medium onion, finely chopped
• 6 oz (175 g) mushrooms, sliced
• 1 tablespoon flour
• ¼ pint (150 ml) semi-skimmed or whole milk
• 1 tablespoon grated Parmesan cheese

Method:

1. Cook the spinach in a large pan, just covering the leaves with water, for 5 minutes. Drain thoroughly and chop finely.
2. Place in a bowl with the egg yolks, salt, pepper and nutmeg to taste. Mix well. Whisk the egg whites until stiff and fold into the mixture.
3. Spread the mixture evenly in a lined and greased 12" x 8" (30 cm x 20 cm) Swills roll tin.
4. Cook in a pre-heated oven at Gas Mark 6 (400°F/200°C) for 10 to 15 minutes until risen and firm.
5. Heat the oil in a pan, add the onion and fry until soft. Add the sliced mushroom and fry for 2 to 3 minutes. Stir in the flour, then gradually stir in the milk. Add salt and pepper to taste and simmer for a couple of minutes more.
6. Sprinkle the cheese over a sheet of greaseproof paper. Turn the roll out onto the paper and peel off the lining paper.
7. Spread with the filling and roll up like a Swiss roll.
8. Serve hot.