Slice the chicken breasts into two. Rub some salt and pepper on each side to taste. Drizzle with 1 tbsp of freshly squeezed lemon juice. Reserve.
Heat the olive oil in a large, deep 3-quart sauté pan. Fry the chicken for 10 minutes a side. Wait until the breasts turn golden brown and completely cooked through.
Transfer the chicken to a plate and use the same pan to sauté the garlic and onions for 5 minutes. Toss in the mushrooms and leave for 5 more minutes or until some juices are produced and the base of the pan looks clean when stirring.
Pour half a cup of the heavy cream into the pan. Cook for another minute until boiling. Remove from the heat. Top with the parsley and lemon zests. Add the lemon juice. Taste and sprinkle some salt and pepper to your liking.
Serve the chicken breasts coated with the sauce. Enjoy with cauliflower parmesan patties and a side of herb salad.