Start by ensuring your chicken breasts are about ½-inch thick for even cooking. Use a meat mallet or butterfly larger pieces if needed. Mix the Italian seasoning, paprika, salt, and pepper in a small bowl, then rub generously on both sides of the chicken.
Heat the avocado oil in a large pan over medium heat. Once hot, sear the chicken for 3-5 minutes per side until golden brown and fully cooked. Remove from the pan and set aside to rest.
Reduce the heat to medium-low and melt the butter in the same pan. Add the onions and cook until soft and translucent, about three minutes. Toss in the minced garlic and stir for an additional minute to release its aroma.
Deglaze the pan by pouring in the chicken broth and scraping the flavorful bits from the bottom. Bring to a boil, then add the penne pasta. Stir well to submerge the pasta, cover, and cook for 10 minutes, stirring occasionally, until the pasta is al dente.
With the heat off, stir in the parmesan cheese, heavy cream, and a handful of parsley. Mix until the sauce becomes thick and creamy. Taste and adjust seasoning with salt and pepper.
Slice the cooked chicken into strips and toss it back into the pan with the pasta and sauce. Stir gently to coat everything evenly. Serve immediately, garnished with extra parsley and parmesan, if desired.