。
She made me a wonderful meal.
Literal
She [topic-は] very wonderful meal [object-を] make-did-the-favor-of.
~てくれる explicitly marks the cooking as a kindness done to the speaker — leaving it out would make the sentence feel oddly distant, like the dinner was merely produced rather than offered. すばらしい ('wonderful, splendid') is at the high-praise end of the i-adjective range, more emphatic than いい or 美味しい would be on their own.