Pat chicken breasts dry with paper towels and season both sides generously with salt and black pepper. Heat olive oil in a large skillet over medium-high heat until shimmering. Place chicken in the pan and let sit undisturbed for 6-7 minutes until a deep golden-brown crust forms. Flip and cook the other side for another 6-7 minutes until internal temperature reaches 165°F. Transfer to a plate and set aside.

In the same skillet with the browned bits, melt butter over medium heat. Add minced garlic and cook for 30 seconds until fragrant. Add whole peppercorns and toast for 1 minute to release their oils. Pour in heavy cream slowly while stirring and scraping up the browned bits. Let simmer for 2-3 minutes until slightly thickened. Stir in parmesan cheese until melted and smooth. Taste and adjust salt. Return chicken to skillet, nestling it into the sauce, and keep warm.

Cook French fries according to package directions if using frozen, or until golden if using fresh-cut potatoes. While hot, season with salt and fresh parsley. Keep in a warm place, ideally in a low oven, until ready to plate.

Divide creamy pepper chicken between serving plates, placing each breast in the center and spooning sauce around it. Arrange hot fries alongside the chicken. Sprinkle fresh chopped parsley over chicken and sauce. Add a pinch of chili flakes if desired and a final crack of black pepper. Serve immediately while everything is hot.