。
She made him a delicious meal.
Literal
She [topic-は] he [for-に] delicious meal [object-を] [made-for-him-作ってやった].
~てやる attaches the rougher 'give' auxiliary onto 作る ('make, cook') for an action done for someone's benefit, here marked with に. The pairing ~を作ってやる is very common in family contexts (cooking for one's children, partner, etc.) — a typical example of how Japanese encodes who-benefits-from-the-action right into the verb morphology.