Wash the meat, dab dry. Heat 2 tablespoons of oil in a large frying pan and fry the meat thoroughly all around. Take it out, season with salt and pepper and let it cool down a bit. Set the pan aside with frying fat. Clean and trim the mushrooms. Cut 200 g into thin slices, the rest into thick slices and set aside
Peel and finely chop the onion. Wash parsley, shake dry. Pluck off leaves and chop finely, except for something to garnish. Heat 2 tablespoons of oil and fry thin slices of mushrooms. Add the onion and fry briefly. Pour into a bowl, stir in parsley and allow to cool. Drain mozzarella and cut into slices. Place between kitchen paper and squeeze excess moisture out of the slices
Take the strudel dough out of the fridge. Let the dough sheets rest at room temperature for about 10 minutes. Melt 100 g butter in a small pot. Clean the carrots, leaving a little green. Peel and wash the carrots. Spread a damp cloth on the work surface. Roll out the dough sheets. Place 2 pastry sheets slightly overlapping to form a rectangle (approx. 30 x 53 cm) on the cloth. Brush with some butter and place 2 dough sheets on top. Brush with butter. Continue like this until the dough sheets are used up
Sprinkle breadcrumbs over the dough. Mix liver sausage with the mushrooms. Spread the liver sausage cream on the lower third of the long side of the pastry sheet and spread it. Spread mozzarella slices on top. Place the fillet on top. Fold the short sides over the fillet, then roll up from the long side. Place on a baking tray lined with baking paper. Spread with the rest of the butter. Bake in the preheated oven (electric cooker: 200 °C/ convection oven: 175 °C/ gas: level 3) for 25-30 minutes. Cover if necessary for the last 10 minutes.
Peel, wash and chop the potatoes. Cook in boiling salted water for about 20 minutes. Melt 25 g butter in a saucepan, fry carrots in it. Season with salt, pepper and sugar. Cover and cook over a mild heat for about 10 minutes. Fry the rest of the mushrooms in the hot frying fat in the pan set aside. Dust with flour and sauté while turning. Deglaze with cream and stock while stirring. Let simmer for about 5 minutes
Roast the almonds in a pan without fat, take them out. Drain the potatoes and let them evaporate briefly. Add 2 tablespoons butter, milk and liqueur and crush everything coarsely. Season to taste with salt and nutmeg. Mix about half of the flaked almonds into the puree and sprinkle with the remaining flaked almonds. Season the sauce with salt and pepper. Take the fillet out of the oven and serve with carrots, sauce and puree. Garnish with set aside parsley