Place the chicken in between two pieces of plastic wrap and pound with a meat mallet until ⅓ inch thick. Season the chicken with the pepper and salt.

In a large sauté pan, heat 1 tablespoon of the olive oil over medium-high heat.

Bring a large pot of water to a boil for the pasta.

Add the chicken to the pan with the olive oil. Cook for 6 minutes over medium-high heat. Flip and sear for an additional 6 minutes or until the chicken is golden brown on both sides.

While the chicken cooks, cook the spaghetti to al dente according to the directions on the package.

Reserve ½ cup of the starchy pasta water before draining.

Once the chicken is browned, remove from the pan and set aside on a plate. Add the remaining olive oil to the same pan used to sear the chicken. The brown bits in the pan will add more flavor to the sauce, so no need to clean the pan!

Turn the heat down to low and add the onion and garlic to the pan. Sauté for 3 minutes until fragrant and translucent.

Once the onions and garlic are cooked, turn off the heat on the stove.

Add lemon zest, lemon juice, and reserved pasta water to the pan with the onions and garlic. Stir together. The oil from the pan and starchy pasta water will begin to form a sauce that will thicken.

Add the spaghetti to the sauce and stir to coat in the sauce.

Add the arugula and Parmesan to the pasta. Stir to combine.

Slice chicken and add to the spaghetti. Garnish with the parsley and enjoy!