Bring a large pot of salted water to a boil.
Add the elbow macaroni and cook according to the package instructions until al dente.
Drain the macaroni, rinse with cold water to stop the cooking process, and repeat. This ensures the pasta is cool and ready to absorb the dressing.
Transfer the macaroni to a large bowl, toss with olive oil to prevent sticking, and set aside.
In a separate bowl, whisk together the mayonnaise, Creole mustard, red wine vinegar, lemon juice, hot sauce, Cajun seasoning, smoked paprika, black pepper, and cayenne pepper (if using).
Add 2 teaspoons of salt and 2 tablespoons of water, gradually adding up to ¼ cup of water to achieve a thinner consistency if necessary.
Stir in the minced onion, diced celery, adouille sausage and diced hard boiled eggs.
Pour the dressing over the cooked macaroni and toss to combine thoroughly.
Taste and adjust the seasoning with more salt, pepper, or hot sauce as needed.
Serve immediately, garnished with fresh parsley and sliced hard boiled eggs if desired, or refrigerate until ready to serve. If the salad seems dry after refrigerating, add a little water to refresh it before serving.