Set a large pot of water on to boil. If you're using wooden skewers, soak them in water.
Whisk the 90 grams shiratamako and ¼ teaspoon salt together in a large bowl and then pour in the ¼ cup + ½ tablespoon water. Whisk together until the flour is evenly hydrated and crumbly.
90 grams shiratamako, ¼ teaspoon salt, ¼ cup + ½ tablespoon water
Use your hand to knead the dough into a smooth mass. If the dough is too wet, knead in a bit more shiratamako. If it's too dry and crumbly, knead another teaspoon of water. The dough should be about the texture of playdough.
Use a scale to portion the dough and roll it into spheres with your hands. Each ball should be about 9.5 grams (⅓ ounce), and you should have around 16 balls.
Gently roll the shaped dango into the boiling water and let them cook for a minute before giving them a stir. If you double this recipe be sure to use a large pot of water, or boil them in batches.
Cook the rice dumplings until they float to the surface, and then set a timer for 2 minutes.
When the timer is up, transfer the dango to a bowl of cold tap water to chill before draining.
Skewer four dumplings per skewer.
Heat a seasoned cast iron skillet until scorching hot.
Whisk the ¼ cup water, 2 tablespoons mirin, 1 tablespoon rice syrup, 1 tablespoon kokutou, 2 teaspoons soy sauce and 1 teaspoon potato starch together in a separate pan until the starch has dissolved.
¼ cup water, 2 tablespoons mirin, 1 tablespoon rice syrup, 1 tablespoon kokutou, 2 teaspoons soy sauce, 1 teaspoon potato starch
Add the dumpling skewers to the hot pan making sure they don't stick together, and grill until they're browned on one side. You can use a spatula to press down on them, so they brown evenly.
Turn the heat on for the sauce and bring the mixture to a boil while stirring constantly. Continue boiling the sauce until it's thick, but not so much that it turns gloppy. Remove the sauce from the heat.
Once the skewers have browned on one side, flip them over and brown the second side.
Plate the finished Mitarashi Dango and spoon over the sauce.