Season the chicken breasts with kosher salt and pepper.

Place a cast iron skillet over medium high heat. When the pan is hot, add the olive oil. Add the chicken breasts and sear until well browned. When the chicken is golden and releases from the pan, flip them over and brown on the other side. When both sides are brown, remove the chicken to a plate and set aside.

Turn the heat down to medium and add the butter. Add the chopped onions and sauté for 2 to 3 minutes until softened and translucent. Add the sliced mushrooms and sprinkle with a bit of kosher salt. Sauté for about 5 minutes until the mushrooms are tender.

Add the minced garlic and cook for another minute over medium high heat until the garlic is fragrant. Remove the pan from the heat and add the whiskey. Stir and then return to a low heat for 2 minutes. Stir in the chicken broth and the heavy cream.

In a small bowl or cup, stir together the flour and 4 tsp. water (20ml) until it is a smooth paste. Add the flour mixture to the sauce and quickly stir to combine. Bring the sauce to a simmer to thicken. Add the chicken breasts back to the pan along with any juices on the plate. Season to taste with salt and pepper.

Finish the sauce with the fresh lemon and chopped fresh parsley.