According to the description in Kakai-sho Commentary, Tsubaki-mochi was something like a dumpling made from mochi-ko (rice cake flour, present-day domyojiko [dried and granulated glutinous rice flour]) that was made by grinding dried glutinous rice with a mill-stone, kneaded with amazura (traditional sweetener commonly used in the past), and wrapped with camellia leaves.
河海抄の記述によれば、もち米を乾燥させて臼でひいて作った餅粉（現在の道明寺粉）を甘葛の汁で練って団子のようにし、椿の葉で包んだもの。