Avocado & Negitoro Donburi

Bahan-bahan (2 porsi)

• ½ lb maguro tataki (chopped tuna for negitoro)
• 1 avocado ((cut into ¼-inch cubes; see Notes))
• 1 g reen onion/scallion ((use if the negitoro package didn't come with green onions; sliced thin))
• 2 servings cooked Japanese short-grain rice ((typically 1⅔ cups (250 g) per donburi serving))
• ¼ cup shredded nori seaweed ((to garnish))
• 1 tsp toasted white sesame seeds
• 2 Tbsp mentsuyu (concentrated noodle soup base)
• 2 tsp soy sauce