The widow displays extraordinary faith by following the prophet's instructions, stepping into the unknown with her last bit of food. Her obedience unlocks a steady flow of miraculous abundance that sustains her and those around her for a long time.
The unfolding of this miracle contains a duality regarding who was the primary focus and cause of the blessing. On one level, the sequence of events places the prophet first. The widow acted exactly as instructed, preparing the food for Elijah before tending to herself [רלב״ג]. In this light, the household was able to eat entirely because of the prophet's merit [רד״ק].
At the same time, an underlying perspective places the woman first, revealing that she was actually the main focus of the miracle. The blessing rested upon her home specifically for her sake. Elijah was secondary in this regard, sustained by her merit, just as God had promised him earlier that a widow would provide for him [מלבי״ם, רד״ק]. The action of eating is directly centered around the widow, cementing her primary status in the event [רד״ק].
Because of this blessing, the abundance expanded far beyond her original expectations. Initially, the widow planned to prepare a final meal only for herself and her son, as her meager natural supplies dictated that they prioritize their own survival. However, the miraculous provision was so great that it easily fed her extended family and the rest of the household [רד״ק, ביאור שטיינזלץ]. This period of miraculous sustenance lasted for a long time [ביאור שטיינזלץ], which traditional sources understand to be a full year [מצודת ציון].