The "voice" of a sentence (or clause) determines the relationship between subject and predicate. The term “active” refers to the “voice” of a sentence, and denotes that the subject of the sentence is the “do-er” or “actor” described. In your sentence, “the writer” is the subject, and “has enjoyed” is the predicate; consequently, the sentence is already technically in the active voice. But a stronger sentence might be: “The writer (of this recipe) has cooked and enjoyed Beef Stroganoff three ways: with rice, with potatoes, and with pasta.” The passive voice looks like this: “Beef Stroganoff is cooked with potatoes, pasta, or rice, by me.” Here, the subject (beef stroganoff) is acted upon (is cooked). The voice of a sentence (or clause) determines the relationship between subject and predicate.