Remove the fat visible inside the body cavity of the goose. Remove giblets, put in pan and boil with 3 cups of water over low heat. Place the goose in a roasting pan (breast-side down), rub outside of the goose with olive oil. Apply garlic, salt and pepper to the skin. Place the thyme, bay leaves, apples, onions and celery in the body cavity. Lace the body cavity closed. Prick the skin with a fork over the surface of the goose. Put 3 cups of water in the pan.
Place goose and pan in oven preheated to 500 degrees Fahrenheit for 30 minutes. Reduce heat to 400 and roast an additional 30 minutes.
Remove from oven. Syphon off drippings or pour into bowl. Turn the goose so the breast is up. Prick the breast again with a fork. Reinsert into the oven and roast for another hour at 400 degrees.
Pour the drippings and the remainder of the water in the pan. Roast an additional 90 minutes.
Remove from oven, pour off drippings for the gravy. Place the goose on a platter, cover with an aluminum foil tent for 15 minutes.
Meanwhile, skim seven tablespoons of the drippings fat and place in a pan over low heat, stirring constantly with a whisk. Add flour slowly after 1 minute, then cook an additional 3 minutes. Add broth and 2 cups of drippings. Increase temperature to medium, stir the gravy constantly until smooth and thickened. Add chopped giblets if desired. Stick a fork in the goose's ass, he's done.