This is the perfect summertime salad. Sometimes I’ll add sliced black olives and/or small chunks of cheddar if I have it. Some people like to add peas , diced onions, or hard boiled eggs. Make it however you like!
Cook pasta in a large pot of boiling salted water until done. Drain.
Marinate macaroni in Italian dressing for 2 to 3 hours or overnight.
Mix sour cream, mayonnaise, onion, celery, garlic powder, tuna, and salt and pepper into macaroni. Chill before serving.