Marinate the beef steaks with a little soy sauce, salt, black pepper, and mustard.

Cut the onions into large pieces.

Heat a grill pan with a little oil and cook the steaks.

Once the steaks are cooked to your desired doneness, add the onions.

Sauté until the onions reach your preferred tenderness.

For the sauce, crush the head of garlic and add one tablespoon of white vinegar.

Dissolve the curry in a little hot water, then mix with mayonnaise, mustard, grated white cheese, and the garlic-vinegar mixture.

Serve the steak with onions and top with as much curry sauce as you like.