Place nanohana and 1 tbsp water in a microwave-safe container. Cover loosely with plastic wrap and microwave at 600W for 1 minute. Rinse with cold water and drain well. Separate 8 flower parts for garnish and roughly chop the rest.

Cut the atsuage into 8 equal pieces, keeping the long side horizontal.

Mix sake, sugar, miso, and white sesame seeds in a bowl. Add the chopped nanohana and mix well to create nanohana miso.

Place the atsuage pieces on a baking tray lined with aluminum foil, cut side up. Top each piece with an equal amount of nanohana miso. Toast in a toaster oven for about 5 minutes until golden brown.