rice cake
餈 centers on a specific food: a rice cake, made from pounded glutinous rice.
餈 combines 食 (food, eating) with 次, which likely contributes the sound. The character specifically refers to a rice cake.
The top 次 suggests 'next' or 'order', and the bottom 食 is food. Imagine the next food in line at a festival is a freshly pounded rice cake.
For シ, picture a sheaf of rice being pounded into a cake: sheaf -> シ, and the rice cake is made from that rice.