この料理は代々伝わる秘伝のレシピで作られています。
This dish is made from a secret recipe handed down through generations.
店の味の決め手は、創業以来の秘伝のたれだ。
The key to the shop's flavor is its secret sauce, kept since the day it opened.
師匠は最後の弟子にだけ秘伝を授けた。
The master passed on his secret technique only to his last disciple.