Cheese roulade

1 - Preheat the oven to 190°C (375°F/Gas 5). Grease and line the Swiss roll tin with greaseproof paper.

2 - Melt the butter in a large saucepan, add the flour, and stir until evenly blended. Remove the pan from the heat and gradually beat in the milk, return to the heat and bring to the boil, stirring constantly, until the sauce is thick and smooth. Remove from the heat again and stir in half the Parmesan, the mustard, and seasoning. Allow to cool slightly, then add the egg yolks and beat until well incorporated.

3 - Using a hand whisk, beat the egg whites in a large bowl until they stand in soft peaks. Mix a large spoonful of the egg whites into the sauce, then gently pour the sauce over the remaining egg whites, and carefully fold together. Take care not to over-mix. Spread the mixture evenly into the prepared tin.

4 - Bake for 15-20 minutes, or until golden brown and the top springs back when touched lightly. Turn out on to a large piece of greaseproof paper dusted with the remaining Parmesan.

5 - Peel away the paper and trim off the crispy edges of the roulade. Spread the surface with the ricotta, leaving a 2.5cm (1in) gap at one short end, then cover with the watercress. Roll up the roulade, using the paper to help. Cut the roulade into slices to serve.