Gyutan Donburi (with Negi Shio Sauce)

Name: Gyutan Donburi (with Negi Shio Sauce)
Prep time: 10 min
Cook time: 5 min
Total time: 15 min
Cuisine: Japanese
Ingredients: 250 g thinly sliced beef tongue (room temperature, about 5mm thick, membrane removed); salt; 1 tsp beef suet (fat) (or neutral cooking oil); 2 ptn cooked Japanese short-grain rice; 100 g Japanese leek (naganegi) (finely diced, or regular leek white parts, or green onions); 2 tbsp toasted sesame oil; 1 tsp lemon juice; 1 tsp honey (or sugar); 1 clove grated garlic; ½ tsp sea salt; ½ tsp Chinese-style chicken bouillon powder (or dashi granules); ½ tsp yellow miso paste (awase); ¼ tsp Japanese soy sauce (koikuchi shoyu); ⅛ tsp ground black pepper; toasted white sesame seeds; chopped green onions; wasabi paste