noun
char siu; roasted pork fillet (often in ramen)
A Chinese-style barbecued pork, typically seasoned and roasted, commonly sliced and served as a topping for ramen or in other dishes.
from Chinese chāshāo
ラーメンにチャーシューを三枚トッピングした。
I topped my ramen with three slices of char siu.
この店のチャーシューは柔らかくておいしい。
The char siu at this shop is tender and delicious.
焼き豚 is a more general Japanese term for roasted pork, while チャーシュー specifically refers to the Chinese-style seasoned and roasted pork often used in ramen.
From Chinese 叉燒 / 叉烧 (chāshāo), referring to a style of barbecued pork.