。
She prepared a feast for us.
Literal
She [topic-は] us [for the sake of-のために] feast [object-を] prepared.
Two cultural threads to notice. First, 私達のために uses ~のために in its beneficiary sense — 'for the sake / benefit of us' — distinct from its purpose use ('in order to'). Second, ごちそう (御馳走) is more than just 'food' or 'a meal': it means a special spread laid out for guests, the kind of effortful hospitality embedded in expressions like ごちそうさまでした ('thank you for the meal,' said after eating). The kanji 馳走 literally means 'running about,' evoking the host's effort to gather and prepare ingredients — a historical metaphor that survives in the modern word.