Bring a medium saucepan of salted water to a boil.

Add the shrimp to the boiling water and cook for 2-3 minutes or until they turn pink.

Remove the shrimp and place them in a colander to drain. Rinse them under cold water to stop the cooking process.

In a large mixing bowl, whisk together mayonnaise, lemon juice, Dijon mustard, salt, and pepper.

Add the cooled shrimp, crabmeat, celery, red bell pepper, and red onion to the bowl. Gently fold the ingredients to keep the crabmeat intact.

Cover the bowl and refrigerate for at least 15 minutes.

After chilling, taste the salad and adjust seasoning if needed.

Transfer the salad to a serving dish and garnish with fresh parsley.