Start by preparing your ingredients. Place the diced red onion in a small bowl and cover with cold water. Let it soak for 20 minutes (or as long as it takes you to prepare the other ingredients) to make it less pungent and then drain the water away.

Bring a large pot of water to the boil. Season the water generously with salt and cook the pasta al dente according to the package instructions. Drain and rinse the pasta with cold water. Let the pasta drain well and then set it aside in a large bowl.

Toast the pecans by tossing them in a dry skillet over medium heat for 5 to 10 minutes or on a sheet pan in the oven at 350ºF for 10 minutes. Set the toasted pecans aside.

Season the chicken breast with the dried thyme, salt and freshly ground black pepper. Pre-heat a skillet over medium-high heat. Add a little olive oil to the pan and sauté the chicken breast for 5 to 6 minutes on each side until cooked through. Transfer the chicken to a cutting board, let it rest for 5 minutes and then cut the chicken into ½ -inch cubes. Add the chicken to the bowl with the pasta.

Drain the red onion and pat it dry with a clean paper towel. Add the onion to the bowl with the chicken and pasta, along with the toasted pecans, celery, grapes and parsley.

Combine the mayonnaise, apple cider vinegar, and Dijon mustard in a small bowl. Add half of the dressing to the bowl and stir to coat everything with the dressing.

Season with salt and freshly ground black pepper to taste. Chill for at least 30 minutes. When ready to serve, stir the salad and add more dressing as needed. (The pasta will absorb the dressing as it sits.)