Heat a large stainless steel or cast iron pan to medium heat.
Pat the chicken thighs dry with paper towels and season with kosher salt on both sides. Sprinkle the coarse peppercorns onto one side of the chicken and press the peppercorns into the chicken.
Add the oil to the hot pan and once shimmering add the chicken, non-peppered side down. Cook for 8-10 minutes or until well browned then flip and cook for about 2-3 minutes on the pepper side of the chicken. Place the seared chicken on a plate and tent with foil.
Pour off the excess fat from the pan, leaving until 3 tablespoons, and add the shallot and a pinch of salt. Cook for 2-3 minutes or until soft. Remove the pan from the heat and add the cognac. Place the pan back on the heat and turn the heat to high, scraping the bottom of a pan with a wooden spoon to dislodge the brown bits. Cook until the cognac is almost evaporated.
Add the chicken stock and reduce by half. Turn the heat down to medium and add the cream. Bring the sauce to a simmer and cook until the sauce almost coats the back of a spoon.
Add the chicken and any accumulated juices, pepper side up back to the sauce and simmer for 3-4 minutes of until warmed through. You can spoon some of the sauce on top of the chicken, but not too much so as not remove the pepper.
Taste test and season with salt and if needed more coarse black pepper. Turn off the heat and whisk in the butter, one cube at a time. Sprinkle the parsley. Serve over mashed potatoes, rice, egg noodle or with crusty bread on the side. Enjoy!