Sesame Tuna and Spinach Salad

Heat a dry pan over medium-high heat and sauté the spinach until it starts to lose its firmness, about 1-2 minutes. Transfer the wilted spinach into a strainer to let it cool down.

Meanwhile, toast white sesame seeds in the same pan over medium heat until they turn a light golden color. Transfer these toasted sesame seeds into a mortar and pestle, and use the pestle to crush them into a coarse paste. Make sure some of the sesame seeds remain whole. Add white sugar, soy sauce, and mirin to the mortar and stir everything together with a wooden spoon. Set this mixture aside for now.

Once the spinach has cooled, use a towel to gently squeeze out any excess moisture. Chop the spinach roughly and add it to a mixing bowl. Add the dressing you prepared earlier, and mix everything together until well combined. Cover the bowl with plastic wrap and refrigerate it thoroughly before serving.

In a separate container, whisk together mayonnaise, miso paste, and rice vinegar to create the miso mayo sauce. Place this sauce in the refrigerator until you're ready to serve.

Sprinkle a pinch of salt over the tuna steaks and then coat them evenly with sesame seeds, pressing them gently onto the fish as you go.

Heat a non-stick pan over medium heat and brush it with oil. Place the tuna steaks in the hot pan and sear them for 30-45 seconds on each side, making sure to cook the edges as well. Remove the tuna from the pan and place it on top of the miso mayo sauce.

Drizzle a small amount of ponzu over the tuna and serve it alongside the spinach salad.