Take the meat out of the fridge approx. 1 hours before. Preheat oven to 80 degrees and heat up the plates.

Chop the mushrooms and slice the onions. Finely chop garlic and sage. Heat oil in a frying pan and fry the mushrooms for approx. 10 mins until liquid has evaporated. Reduce the heat before adding the onions, sage and garlic. Cover and sauté for approx. 10 mins. Add the cognac while reducing the heat completely, season and leave the filling to cool down. Cut into the middle of the meat lengthwise and make sure the incision is approx. 4cm wide. You can use the end of a spoon the make the pocket bigger if necessary. Then, fill the pocket with the mushroom filling.

Heat oil in a frying pan. Season the meat and brown all over for 5 mins. Turn only when a crust has formed. Place meat on warm plate and put the pan to the side.

Put the meat in the centre of the preheated oven for approx. 1 1/4 hours.

Peal potatoes, celery and pear and cut into pieces. Place steamer basket in a wide pan and fill the basket with water so it just touches the bottom of the basket. Add vegetables and pear, cover and cook for approx. 30 mins until soft. Remove the steamer basket containing the vegetables and pear and pass them through a food mill and eventually back into the pan. Stir in butter and season. Then cover it and leave it aside.

Pour the cognac into the frying pan and lower the heat to the min. Pour in the single cream, simmer for approx. 2 mins. Carve the meat across the grain and serve with celery & pear puree and the cream sauce.

Put the stir fry onto a warm plate and sprinkle the dish with the peanuts. Serve and enjoy!