Place carrots, onion, celery, turnip, apple and garlic in a food processor and pulse until you have a coarse textured puree. Once roasting pan comes out of the oven (and meat is removed) set it over medium-high heat on the stove. Add a 2-count of olive oil then add vegetable puree. Sweat for 7 to 8 minutes until most of the moisture has cooked off, then dust with flour. Cook for 2 more minutes stirring well to incorporate all the flour with the fat in the pan. Add the apple liqueur and scrape the bottom of the pan. Gradually add chicken stock, stirring as you go to ensure there are no lumps. Bring to a simmer and season well with salt and pepper. Simmer then remove from heat and strain through a sieve - it's okay if some of the pulp goes through as this will naturally add body to the gravy. Serve with roast and stuffing.