。
She heated up the cold soup for dinner.
Literal
She [topic-は] chilled soup [object-を] dinner [for-に] warmed.
冷えた (ひえた, past of 冷える 'to get cold') functions as a prenominal modifier — 'soup that has become cold.' 暖めた (あたためた, 'warmed up') is the main verb. 夕食に ('for dinner') uses に to mark the purpose/occasion.