rice cake
餠 centers on a specific food: a rice cake made from pounded glutinous rice. The meaning is concrete and narrow, without broad abstract extensions.
餠 combines 飠 (food) with 幷, which likely contributes the sound. The character is a traditional form; the modern simplified Japanese form is 餅.
The food radical 飠 on the left suggests something edible, and the right side 幷 looks like a stack of pounded rice cakes. Together they make 餠, a rice cake.
For ヘイ, imagine a heavy rice cake being pounded: the sound of the mallet is a heavy 'hey!' -> ヘイ, as the rice cake takes shape.