sticky rice ball
麭 centers on a sticky rice ball, a specific type of food made from glutinous rice.
麭 combines 麥 (wheat) with 包 (wrap), suggesting a food item wrapped or made from wheat or grain. The exact historical development is uncertain.
The left side 麥 means wheat or grain, and the right side 包 means wrap. Imagine a sticky rice ball wrapped in a wheat-flour coating.
For ホウ, picture a sticky rice ball wrapped in a leaf and held in your hand: you hold it, and 'hold' sounds like ホウ.