Beef Wellington

Preparation

• 1
  Using a knife, trim the beef tenderloin, rub it well with pepper and mustard, then place it in a bowl just large enough to hold it. Pour enough oil over it to just cover it, and marinate it covered in the refrigerator for 3-4 days.
• 2
  Rub the slightly drained marinated beef tenderloin with about 1 teaspoon of salt. Heat a little of the oil used for marinating in a pan, and sear the meat on all sides for 7-8 minutes. Drain and let it cool, then wrap it in cling film and chill thoroughly.
• 3
  Thaw the puff pastry at room temperature. Grate or finely chop the cleaned mushrooms and onion, and sauté them in 3-4 tablespoons of the oil used for marinating the meat, stirring until all the liquid has evaporated. Then season with salt and pepper, and continue to sauté briefly with the breadcrumbs. Finally, pour in the 2 beaten eggs and cook until set. Remove from heat and season with chopped parsley.
• 4
  On a lightly floured board, roll out the pastry to a rectangular shape, 1 cm thick. Spread the pre-seared meat with the mushroom mixture, and place it in the center of the pastry. Brush all sides well with the mixed egg, then fold the pastry over and place it seam-side down on a baking tray lined with baking paper. Brush with the remaining beaten egg, prick in a few places with a fork, and bake in a preheated oven at 180 degrees Celsius for about 30 minutes. Rest for 10-15 minutes before serving, then slice about a finger's width thick. Boiled potatoes, mashed potatoes, or a vegetable side dish are suitable accompaniments.