Season the inside of the lamb breast with salt and pepper. Cut the liver into small cubes and mix with the remaining ingredients for the filling. Spread evenly on the lamb breast, fold and roll up, tie with spaghetti.
Heat clarified butter in a roasting pan and brown lamb breast on all sides. Extinguish with a little water and roast in a heated oven at 200 °C for about 90 minutes. Remove and keep warm.
For the sauce, boil the roast stock with the beef broth, pass it through a sieve and add the whipped cream. Cook a little and season with salt and pepper.
Serve with broccoli with diced tomatoes and potatoes.