Boil the pasta in salted water according to the package instructions. Penne typically takes 10-12 minutes to cook to al dente.
In a small bowl, combine all of the seasonings and set aside.
Beat the chicken breasts to an even thickness with a meat mallet.
Season both sides of the chicken with cajun seasoning. Reserve half of the seasoning for the pasta.
Heat a large skillet on medium-high heat and add the oil. Once the skillet is hot, add the chicken and sear for 2 minutes per side or until each side is golden brown. Turn the heat to low, cover the skillet with a lid, and cook for an additional 5 minutes.
Transfer the chicken to a plate and cover to keep warm.
In the same skillet, saute the mushrooms with 1 Tbsp of butter and lightly season with salt and pepper. Cook for a few minutes.
Add the minced garlic, 1 Tbsp of butter, and tomatoes, and saute for 2 minutes.
Turn the heat down to low and add the heavy whipping cream, parmesan cheese, and remaining Cajun seasoning.
Bring the mixture to a light simmer and let it cook and thicken.
Cube up the chicken and add to the milk mixture.
Stir the pasta into the cream sauce.
Top the pasta with parmesan cheese and garnish it with fresh herbs. Enjoy!