Rinse the rice under cold water until the water runs clear, then combine with water in a rice cooker and cook until fluffy (about 20-25 minutes).

Prepare the miso butter by mixing miso, mirin, sake, sugar, and softened butter until smooth.

Let the cooked rice cool for 10 minutes, then divide into six portions and shape each into a triangle using cling wrap.

Preheat your skillet, add vegetable oil or butter for a nice coating, and wait until the butter bubbles.

Place rice triangles in the hot skillet and grill each side for 1 minute, brushing with miso butter until golden brown.

For soy sauce variation, repeat grilling with triangles brushed with soy sauce instead of miso.

Garnish grilled rice balls with butter, chives, and sesame seeds before serving.