Strudels are mainly specialties wrapped in paper thin dough sheets version Wellington made out of puff pastries. Many fish varieties are suitable for this recipe. Scallops and shrimps would do the job too.
Clean fish (skin, bones and bloodlines removed), and cut flesh into chunks. In the food processor, break down fish and add salt, pepper, sugar and give a few pulses. Add melted butter, eggs and cream. Pass fish mousse through a tamis and reserve it in the refrigerator.
Lay a sheet of filo dough onto the work surface (larger side up). Grease with fat and top with another sheet. Pipe out mousse and wrap the log tight (6 o'clock to noon), brush out more fat during the procedure. Divide log into 2 portions for storage (each log serves 4). Keep refrigerated for up to 48 hours. Avoid freezer.
Clean chervil and spinach; set aside. In a saucier, sweat shallots in butter until fragrant. Deglaze with white wine, and reduce by half. Add chicken stock and reduce by half. Do likewise with the heavy cream. Pass liquid and blend with the greens. Add a couple of chunks of cold butter if desired. Blend well and sieve the velouté over a saucepan. Season with salt and pepper.
Turn oven on to 375ºF/190ºC. Heat up a frying pan, add a drizzle of oil or butter or both. Sear fish strudel about 2 minutes on each side. Fish cooking in the oven for about 8 minutes or until internal temperature reached 131ºF/55ºC. Serve fish strudel with the hot green velouté – garnish with caviar if desired. Enjoy!