Use your favorite oven roasted chicken or turkey recipe (See link at bottom for recipe I use). Remove chicken from oven, and transfer to a cutting board with a well. Let chicken stand 10 to 15 minutes so the juices settle. Meanwhile, pour the pan drippings into a shallow bowl or fat separator, and leave onions in the pan. Leave any brown baked-on bits in the bottom of the roasting pan, and remove and discard any blackened bits. Using a large spoon or fat separator, skim off and discard as much fat as possible. Pour the remaining drippings and the juices that have collected under the resting chicken back into the roasting pan. Place on the stove over medium-high heat to cook, about 1 minute. Add 1 cup of chicken stock, raise heat to high, and, using a wooden spoon, stir up and combine the brown bits with the stock until the liquid is reduced by half, about 4 minutes. Strain the gravy into a small bowl, pressing on onions to extract any liquid. Discard onions, and stir in a tablespoon of cold butter or butter substitute like Earth Balance until melted and incorporated. Untie the legs, and remove and discard garlic, thyme, and lemon. Carve, and serve gravy on the side.
Source: Martha Stewart