For the Stuffed Chicken:
Chop 3 cloves of garlic and 3 sprigs of rosemary. Combine in a small bowl with olive oil; add zest of one lemon, juice of 2 lemons, salt and pepper to taste. Add chicken to the marinade and toss to coat. Marinate for two hours room temperature or overnight in the refrigerator.
Preheat oven to 375F. Slice two remaining cloves of garlic thinly and saut in olive oil until slightly brown, remove from heat and cool. Chop remaining leaves of rosemary and add it to the cooled olive oil with garlic. Mix the olive oil mixture with the goat cheese.
Separate the goat cheese mixture into six equal parts and stuff the mixture under the skin of each chicken breast.
Bake in a preheated 375F oven 20-30 minutes.
For the Potatoes Au Gratin:
Preheat oven to 375F. Slice potatoes paper thin on a mandolin.
Place three layers of potatoes in a hotel pan and season with salt, pepper and chopped garlic. Cover with heavy cream and then add shredded Gruyere cheese. Push down on potatoes. Repeat process until pan is full.
Cover with foil and bake until you can put a skewer through the potato, approximately 40 minutes.
For the Blueberry Port Demi-Glace:
Cut garlic in half with the skin on. Cut carrots in chunks (do not peel). Cut the onion in chunks with the skin on. Add peppercorns and saut all in olive oil over medium-low heat constantly stirring until you achieve a nice brown color on veggies. Deglaze pan with 1/2 bottle of port wine, add a diced tomato and 1 bay leaf. Simmer over low heat and reduce liquid by half. Add chicken stock to the pot and reduce liquid by half.
Strain into a new pot and add 1 cup of port wine and the demi-glace to thicken the sauce. Finish with butter.