Bring a pot of water to boil and season generously with salt. Cook macaroni according to package instructions. Drain, rinse with cold water, repeat and transfer to large bowl. Toss with olive oil and set aside.
Meanwhile, combine remaining ingredients in another bowl. Use a whisk to combine all remaining ingredients except celery, onion and egg. Add 2 teaspoons salt and 2 tablespoons of water to start, up to ¼ cup water. When combined, stir in celery, onion and egg. The sauce should be on the thinner side, not too thick.
Taste sauce for seasoning and adjust salt, pepper and hot sauce to taste. Add to cooked elbows and toss to combine. Serve immediately with fresh parsley and/or hard boiled egg slices, or refrigerate until serving, adding a little water to loosen up and make shiny again if needed.