Wagyu Sando Recipe

Make the sauce

In a small bowl, combine 1/2 cup Japanese mayonnaise, 1.5 tablespoons sriracha, 1/2 teaspoon soy sauce (optional), 1/2 teaspoon lemon juice and 1/4 teaspoon toasted sesame oil. Whisk until smooth and taste — adjust heat by adding more sriracha or mellow with more mayo. Refrigerate while you prepare the sandwich so flavors meld.

Slice and season

If using a whole steak, chill briefly until slightly firm and slice very thinly against the grain (about 1/8 inch / 3 mm). Lay slices on a plate and lightly brush both sides with 1 teaspoon neutral oil. Season each side with a light sprinkle of kosher salt (about 1/4 tsp total across all meat) and 1/4 teaspoon freshly ground black pepper.

Sear or quick-grill

Heat a cast-iron skillet or flat-top over high heat until just smoking. Add the wagyu slices in a single layer (work in batches if needed). Sear each side for 20–40 seconds depending on thickness — you want a deep caramelized exterior while keeping interior very rare to medium-rare to preserve wagyu texture and fat. Remove to a plate and tent loosely with foil to keep warm. Reserve any rendered fat in the pan for brushing the bread if desired.

Prepare milk bread

Lightly butter one side of each slice of milk bread with softened unsalted butter (about 2 tablespoons total). Heat a nonstick skillet or griddle over medium-low. Toast buttered sides of the bread until just golden and set aside. Optionally brush the toasted sides with a tiny swipe (1/2 tsp total) of rice vinegar mixed into a few drops of water for a subtle brightness.

Assemble sandwiches

Spread about 1 tablespoon of the spicy mayo evenly on the untoasted side of four bread slices (the inner side). On top of the mayo, layer 2 shiso leaves per sandwich (place whole leaves or tear once if large). Arrange the warm wagyu slices over the shiso — aim for about 2.5 ounces of wagyu per sandwich, slightly overlapping to build a compact filling. Spoon another 1 tablespoon spicy mayo on the inner side of the remaining four slices of bread and close sandwiches, mayo-side down.

Press and finish

Press each sandwich gently with your palm to compact. For a traditional sando profile, wrap sandwiches in plastic wrap and refrigerate for 10–15 minutes to allow fillings to settle (optional). Using a very sharp knife, trim crusts if not already removed and cut sandwiches cleanly into halves or thirds on the bias. Serve immediately while wagyu is still warm (if you skipped chilling) or after brief rest if chilled.

Taste one half and if desired, sprinkle a tiny pinch of flaky sea salt and a few cracks of black pepper over the exposed meat. Serve with extra spicy mayo on the side. Enjoy the Wagyu Sando as a luxurious, soft, and savory sandwich best eaten within an hour of assembly.