The Sando Recipe

Prep the chicken

Pat the chicken thigh dry with paper towels. Trim any excess fat. Lightly flatten the thigh to an even 1/2-inch thickness by placing it between plastic wrap and gently pounding with the flat side of a meat mallet or rolling pin. Season both sides with 1/8 tsp black pepper and a pinch of salt (from the 1/4 tsp). Toss the cornstarch over both sides so it forms a very thin dry coating — this helps the exterior crisp.

Marinade/sauce mix

In a small bowl combine 1 tsp soy sauce, 1 tsp mirin, 1 tsp sugar, grated ginger and minced garlic. Stir until sugar dissolves. Reserve about 1/2 tsp of this mixture to brush on the finished chicken. Mix the remaining marinade into 1 tablespoon mayonnaise (or Kewpie) to make a slightly sweet-savory mayo spread; set aside.

Cook the chicken

Heat a nonstick or cast-iron skillet over medium-high heat. Add 1 tsp neutral oil and 1 tsp unsalted butter. When butter foams, add the chicken thigh. Sear 3–4 minutes on the first side without moving until a golden crust forms. Flip and reduce heat to medium. Spoon the reserved small amount of marinade over the top, cover and cook 3–4 more minutes until the internal temperature reaches 165°F (74°C). If using a thicker thigh, add 1–2 more minutes. Remove chicken to a plate and let rest 3 minutes, then slice to fit the bread (about 3–4 slices).

Egg wash (optional tamago-style)

In a small bowl beat 1 egg with 1 tablespoon milk and a pinch of salt. Heat a small nonstick pan over medium-low and butter lightly. Pour in the egg to make a thin omelette about the size of a slice of bread. Cook quickly 1–2 minutes until set but still tender. Fold or roll to fit the bread. This yields a soft, eggy layer common in many sandos. (If you prefer no egg, skip this step.)

Toast bread

Lightly butter one side of each bread slice (optional). Toast or griddle slices butter-side down over medium heat until just golden and slightly crisp, about 30–60 seconds. This prevents sogginess and gives a light crunch.

Assemble the sando

Spread the sweet-savory mayo evenly on the non-toasted sides of both bread slices. On the bottom slice layer shredded iceberg lettuce (about 1/2 cup), then place the sliced chicken thigh across the bread, add the thin omelette (if using), and arrange cucumber slices on top. Spoon pickled red onion if using. Sprinkle sesame seeds and a light dusting of shichimi togarashi or chili flakes to taste. Top with the second bread slice mayo-side down. Press gently and trim crusts if you want the classic Japanese sando look.

Serve

Cut the sandwich in half straight down the middle (or into rectangles), secure with a toothpick if needed, and serve immediately while the chicken is warm. Provide extra mayo or pickles on the side if desired.

If using, sprinkle sesame seeds and shichimi/chili on the assembled sandwich. Use paper towels to blot excess grease from the cooked chicken before assembling to keep bread from getting soggy.