From: Rabbi Moshe Sofer
To: Rabbi Meir
Rabbi Meir proposed that nat bar nat (taste transferred through a vessel intermediary) would not constitute a Torah-level basar bechalav prohibition, applying this to resolve difficulties in the Rashba, Taz, and others. The Chasam Sofer refutes this by showing that the Talmud in Pesachim draws no distinction between the various Talmudic sources for ta'am ke'ikar, proving that taste absorbed directly and taste transferred through a vessel are halachically identical.
Source: Shu"t Chasam Sofer YD §86