Coat the sliced beef with all-purpose flour.

Cut mushrooms in half and slice the onion thinly.

Heat half the butter (10g) in a pan over medium heat and sauté the onions until caramelized. Add mushrooms and cook until softened. Remove from the pan.

Add the remaining butter (10g) to the same pan and cook the beef over medium heat until browned.

Add water, heavy cream, sour cream, salt, and pepper to the pan. Return the onion and mushroom mixture, stir, and simmer covered for 6–7 minutes over low heat.

Mix cooked rice with butter and parsley in a bowl to prepare butter rice.