Lay the chicken out on a cutting board and season both sides with the salt and black pepper.
Heat the oil in a large cast iron skillet over medium-high heat. Once the oil is hot, add the chicken and turn the heat down to medium. Cook until the chicken is browned on the outside and fully cooked inside. This takes about 3 to 4 minutes on the first side and about 2 to 3 minutes on the second side. Transfer the chicken to a plate and drape a piece of foil on top.
Turn the heat down to low. Add the garlic to the same cast iron skillet and cook 10 seconds, stirring constantly. Add the rosemary, sundried tomatoes, crushed red pepper flakes, chicken stock, and heavy whipping cream. Let it come up to a boil, and then cook for 1 minute, stirring constantly.
Remove from the heat and add the chicken cutlets into the creamy sauce.
Top with grated Parmesan cheese and fresh rosemary or basil if desired. Serve.