In a bowl, combine ground beef, egg, cream, minced onion, and the spices Use wet hands to form the flat patties.
Fry the patties in butter for 3- 4 minutes on each side Put the patties in an ovenproof dish and keep baking in the oven on 210-250° F (100-125° C) while you prepare the rest.
Whisk the cooking juices with some water and set aside for the gravy.
Slice the onions really thin with a sharp knife or mandolin Fry in butter until soft and golden Set-aside
In a saucepan, bring the cream, cooking juices and the rest of the ingredients for the sauce to a boil Simmer over medium heat for 5-10 minutes or until the sauce has the desired consistency Stir in the onions Season with salt and pepper.
Rinse and cut the broccoli into smaller florets Boil for a few minutes in lightly salted water, until crisp-tender Drain and allow to steam for a few minutes.
Serve the beef patties and the onion gravy with the freshly boiled broccoli.