Tzippi: You pose a simple but complicated question.
Rav Blumenkrantz was not concerned about the halachic ways of taking hot food out of a pot which is cooking, or stirring it, or returning it to the fire. That is of course doable.
From what I recall, it did not seem like Rav Blumenkrantz was giving an eitza tova (nice advice) but he felt it was a genuine problem.