Feigning illness, Amnon sets his cunning trap into motion, manipulating King David into sending Tamar directly to his quarters. Driven by his intense desire to execute his scheme, Amnon fails to fully grasp the careful advice given to him by Jonadab. Instead of being patient, he rushes his words and acts prematurely [מלבי״ם]. He immediately demands that Tamar prepare the food right in front of him and then feed him with her own hands.
Completely unaware of the dark intentions, King David focuses only on the initial part of the request. He assumes that his son, suffering from illness and a loss of appetite, is simply craving a specific dish that only Tamar knows how to make perfectly. To the king, the request for Tamar to prepare the food directly in Amnon's sight seems like the natural desire of a sick person who wants to watch the preparation to ensure he is getting exactly the food he loves [מלבי״ם, מצודת דוד].
As for the specific food requested, commentators offer two main descriptions. One approach explains that the dish consisted of dough boiled in scalding water [רד״ק, מצודת ציון]. Conversely, others suggest it was a food more familiar to us today, made primarily of dough deep-fried in oil [רלב״ג, ביאור שטיינזלץ]. To complete the illusion, Amnon asks to eat only a small portion. This modest request is perfectly suited to maintaining his disguise as a frail man with a weak stomach who can only manage a few bites [מצודת ציון, רלב״ג, ביאור שטיינזלץ].