惣 means all (archaic); ready-made food and is a JLPT N1 kanji. It has 12 strokes and uses the heart/mind radical (心).
Stroke order · 12 strokes
On'yomi (音読み)
ソウ
Kun'yomi (訓読み)
すべ(て)
Radical
心 · heart/mind
Strokes
12
How to remember 惣
Bringing everything together in one's mind (心) — comprehensive. お惣菜 — the ready-made side dishes at the convenience store/supermarket; a bachelor's nightly lifesaver!