Begin by heating a pot of water until it reaches a simmering temperature of 167°F (75°C). Carefully lower in your room-temperature eggs using a slotted spoon and allow them to cook gently for 15–20 minutes.

While the onsen eggs are cooking, take a mixing bowl and combine the soy sauce, sake, mirin, and grated ginger. Whisk until well-blended, then add your thinly sliced Japanese beef.

Toss the beef until it’s thoroughly coated in the marinade and let it sit for about 10–15 minutes.

Heat a skillet over medium-high heat and add the tablespoon of vegetable oil. Once the oil is hot, add the marinated beef in batches, ensuring there’s enough space for even cooking. Sear the beef for about 2 minutes on each side.

After cooking your beef, remove it from the skillet and let it rest briefly. Arrange the seared beef slices on individual plates.

Gently tap the cooked onsen eggs to crack them and carefully peel away the shells. Place one egg atop the arranged beef on each plate.

Sprinkle with freshly chopped scallions and toasted sesame seeds. Serve immediately.