Parashas Bo · Shemos 12:9 · TT note 16
Torah Temimah on Shemos 12:9, note 16 (on צְלִי אֵשׁ) points to Pesachim 41a.
Sefaria — Exodus 12:9
Sefaria — Torah Temimah on Exodus 12:9
Sefaria — Pesachim 41a
E-Daf — Pesachim 41a
English: The Sages taught: One might think that one who roasted it thoroughly [until charred] is liable — therefore it says “You shall not eat of it underdone or cooked in water”; underdone and cooked I told you, and not that one roasted it completely.
Exclusionary derash: the lav does not cover over-roasting to a char.
Over-roasting until the meat is charred is not the prohibition of na or mevushal.