For a richer flavor, use dark brown sugar in the Mitarashi sauce. Adjust the sweetness of the Mitarashi sauce to your preference by adding more or less sugar. To prevent the dango from sticking to the griddle, lightly brush it with oil before grilling. The dango can be prepared ahead of time and stored in the refrigerator. Reheat them on the griddle or in a microwave before serving. Mochiko (sweet rice flour) is essential for achieving the proper chewy texture. Do not substitute with regular rice flour.