Peel and finely chop the onion. Heat the fat in a pot and fry the onion until transparent. Add flour and sweat it. Add cream and stock while stirring constantly. Simmer for ten minutes so that the sauce reduces a little.
Grate the cheese and melt in it. Season to taste with salt and pepper. Wash the lemon and cut into thin slices. Flatten escalope. Season with salt and pepper. Put one lemon slice, two slices of sausage and some parsley leaves on each half of the meat.
Fold the other half over and fix it with wooden sticks. Heat two tablespoons of oil in a pan. Fry the meat on both sides until crispy brown. Then continue to fry for seven minutes at medium heat.
Cook the pasta in plenty of boiling salted water with the remaining oil for seven minutes, drain. Arrange the meat on the noodles. Garnish with a slice of lemon and parsley. Serve with extra sauce.