First prepare the roulade:

1. Melt margarine in a saucepan, stir in flour and cook for 1 minute. Gradually blend in milk and cook over a medium heat, stirring frequently, until the mixture boils and thickens.

2. Whisk in egg yolks and corn. Whisk egg whites until stiff peaks form and gently fold through corn mixture. Spread mixture into a lightly greased and silicone paper lined 25 x 30cm (10 x 12in) Swiss roll tin.

3. Bake at 220 °C/425°F/Gas Mark 7 for 15 - 20 minutes or until puffed and golden.

To make the filling:

4. Whisk together stock, sour cream and basil. Melt margarine in a saucepan, add mushrooms and onion and cook for 5 minutes or until onion softens.

5. Add flour and cook for 1 minute. Gradually stir in stock mixture and cook over a medium heat, stirring constantly until mixture boils and thickens.

6. Turn roulade on to a wire rack covered with a clean tea towel and remove paper. Quickly spread with warm filling and gently roll up from the short side, with the help of the tea towel. Serve with lightly steamed carrots, mangetout and boiled new potatoes.