Wagyu Steak Sandwich with Caramelized Onions

In a skillet over low heat, add olive oil, sliced onions, sugar, and a pinch of salt. Cook slowly until deeply caramelized, then set aside.

Place beef bacon in a cold pan, then turn the heat to medium. Cook until crispy, then remove and set aside.

Trim the large fat cap from the wagyu steak and slice the meat against the grain into very thin strips.

In a hot cast iron skillet, render the trimmed steak fat to grease the pan, then remove the solid piece.

Add the sliced steak to the hot skillet and cook until crispy and browned.

Season the steak with Worcestershire sauce and a generous amount of freshly ground black pepper. Cook for another minute, then remove the steak from the pan.

Lower the heat and add minced garlic and chopped parsley to the pan drippings, stirring for about 30 seconds until fragrant.

Place the sourdough slices in the skillet to soak up the drippings. Toast on one side, then flip.

Grate fresh Parmesan cheese over both sides of the toasting bread.

In a small bowl, prepare the sauce by mixing together sour cream, Dijon mustard, Worcestershire sauce, ketchup, and Cajun seasoning.

To assemble, spread the sauce generously on the toasted bread slices while they are still in the pan.

Layer the sandwich with the cooked steak, a slice of horseradish chive havarti cheese, the crispy beef bacon, and the caramelized onions.

Place the other slice of bread on top, press down, and remove from the skillet. Slice in half and serve immediately.