Preheat oven to 350 degrees F.
To prepare the chicken: Season the chicken with salt and pepper. In a saute pan, heat olive oil and sear skin side down until golden in color, about 3 minutes. Turn and saute another 3 minutes. Transfer pan to oven and roast for 15 to 20 minutes or until done. Remove the chicken from the pan and keep warm.
Remove fat from pan. Add fennel, sage sprig, lemon zest, lemon juice, and raisins and deglaze with 1 cup of white wine and 1/2 cup sweet wine. Over high heat, reduce by half. Add brown chicken stock and cream. Reduce until slightly thickened. Remove sage and finish sauce with butter and grapes.
To prepare the couscous: In a saucepan, heat olive oil. Add onions and cook for 1 minute, until glossy (do not brown). Add pearl couscous and stir until well coated with oil. Season with salt and add 1 cup of chicken stock. Stir occasionally until 2/3 of the liquid is absorbed. Add the remaining cup of stock, and continue to cook until al dente. Taste and adjust seasoning with salt, stir in butter, and finish with parsley. Set aside and keep warm.
To serve: Place a few tablespoons of couscous in the center of a plate. Slice each chicken breast diagonally into 2 pieces. Arrange on top of couscous. Nap with sauce and sprinkle with sage leaves. Serve immediately.
Preheat the oven to 400 degrees F.
Spread the bones and onion slices in a roasting pan and set in the oven. Turn the bones to brown all sides until they are a deep golden brown, about 30 minutes. Do not allow them to burn, since that will give the stock a bitter taste.
Transfer the bones and onion to a stockpot, and place the roasting pan on the stove. Over medium high heat, deglaze the pan with 2 cups of water, scraping up all the bits stuck to the bottom of the pan. Pour into the stockpot and add 3 quarts of water. Bring to a boil, lower heat, and simmer for 3 hours.
Strain into a clean stockpot and boil for 20 to 30 minutes, until the stock is reduced to 2 cups. At this point, the stock is more concentrated and more flavorful. Strain into a clean bowl and cool.
Since brown stock is primarily a base for sauces and only a small amount is used, pour the cooled stock into an ice-cube tray. When completely solid, release the cubes, enclose in a plastic bag, and return to the freezer. When needed, one or two cubes can be defrosted and used in a recipe.
Yield: about 2 cups
Recipe courtesy Wolfgang Puck, "Pizza, Pasta & More!," Random House, 2000 .