To marinate the chicken, add the shawarma seasoning, salt (omit if your seasoning contains salt), vinegar, and olive oil to a medium bowl and stir to combine. Add the chicken breasts, flipping so that both sides are coated in the marinade. Allow the chicken to marinate at room temperature for at least 15 minutes or up to 12 hours, covered in the refrigerator.

Meanwhile, create your garlic sauce. Mince the garlic, sprinkle with a tiny pinch of salt, and use the side of your blade to smash the garlic. Continue mincing until it turns into a paste. You could also do this using a mortar and pestle. Once the garlic is a paste, whisk it together in a bowl with lemon juice and mayonnaise. Alternately, you can also do this in a small food processor, but be sure to use the "pulse" setting so as to not over-whip the mayo, causing it to split. Cover the garlic sauce and place it in the refrigerator until ready to use.

Prepare fries according to package instructions.

While fries are being prepared, heat a cast-iron skillet over medium-high heat. Drizzle with a little oil and cook the chicken breast for 8-12 minutes, flipping halfway through until the chicken reaches an internal temperature of 165°F. Remove the chicken to a plate and allow it to rest for at least 5 minutes before dicing. Alternately, you can grill the chicken.

When the fries are done, top with the diced chicken, onions, tomatoes, and cornichons. Drizzle the prepared garlic sauce all over your Chicken Shawarma Fries and add chopped parsley before serving.