Process the flour, eggs, oil and salt whilst slowly adding the milk until the mixture has the consistency of a single cream. You may not need to add all the milk.

Let the batter rest in the refrigerator for one hour

Put 1 teaspoon of the butter into the frying pan, and once it has melted swirl it around to coat the surface of the pan

Drop a large tablespoon full of the batter into the pan and tilt to spread it around evenly. Cook until golden brown on the bottom then turn and cook briefly on the other side lay the pancake on a wire rack and cook the others in the same way

Cook the spinach over a low heat for about 15 minutes. Strain of the water and let the spinach cool.

Process the spinach in a food processor together with a cream cheese and Roque for cheese until smooth. Turn into a bowl and add half of the walnuts and chervil

Preheat the oven to 190°C

Fellow the pancakes and place in a shallow ovenproof dish rolled tightly and place in rows.

Make the sauce by melting the butter, adding the flour and cooking for a minute or two.

Add the milk and stir constantly into the sauce comes to the boil. Stir in all the other ingredients except for the chervil.

Pour the sauce over the pancakes and bake for 20 minutes, serve immediately is sprinkled with the chopped chervil and remaining walnuts