殼的邊：一排小圓弧
這一支拿的是殼的外緣輪廓，跟食物完全無關。
adjective · B2
Something scalloped has an edge shaped into a row of small curves, so the border looks like a line of little half circles instead of a straight line.
扇貝邊的、波浪邊的
核心畫面
Put one scallop shell on the table and look at it twice. Look at its rim first: it runs in and out in small even curves instead of a straight line. Now turn it over and look at the hollow: it is a small dish, deep enough to hold food and strong enough to go into a fire. The shell's rim is where the shape meaning comes from, and the shell's hollow is where the cooking meaning comes from. One object, two things it is good for.
把一個扇貝殼放在桌上，看兩次。第一次看它的邊：不是直線，而是一個一個小圓弧排過去。第二次把它翻過來看凹的那面：那是一…更多收起
把一個扇貝殼放在桌上，看兩次。第一次看它的邊：不是直線，而是一個一個小圓弧排過去。第二次把它翻過來看凹的那面：那是一個小小的盤子，裝得下東西，也耐得住火。邊緣的形狀，長出了「波浪邊」那個意思。凹進去的容器，長出了「焗烤」那個意思。同一個殼，兩種用途。From the word’s history
Our Wiktionary evidence gives scalloped as scallop plus -ed, and adds that in the cooking sense it first meant a seafood dish baked and served in a scallop shell, and is only now used more generally. That single note explains both branches without needing any guesswork.
手上的 Wiktionary 資料說 scalloped 是 scallop 加上 -ed，並且註明：在料理的意思上，它本來指裝在扇貝殼裡烤、也用殼盛著上桌的海鮮菜，後來才擴大到一般食物。這一條註解剛好把兩支用法都說清楚了，不必再猜。
Wiktionary via supplied kaikki extract 3f6f69a190036ae4, entry 'scalloped' (adj), etymology_text
Two branches
殼當烤盤：奶醬焗烤
這一支拿的不是形狀，而是殼的另一個身分：一個可以進烤箱的小盤子。
adjective · B2
Scalloped potatoes, corn and similar dishes are cut up, covered in a cream or cheese sauce, and baked in the oven until they are soft.
奶醬焗烤的