Roast and prepare the vegetables ahead of time. See Roasted Vegetables for Sweet Potato Eggplant Gravy.
Melt the butter in a large pot over high heat. Add the reserved onions and cook, stirring well, for 2 minutes. Add the mashed garlic and 2 tablespoons of the Meat Magic. Cook until onions are soft and translucent, about 4 minutes, stirring and scraping the bottom frequently. Add the eggplant and the remaining Meat Magic. Stir and scrape well for 2 minutes. Add the Poultry Stock. Increase the heat to high and bring to a boil. Reduce the heat to low and simmer slowly until thick, about 50 minutes. Add the reserved sweet potato and the brown sugar. Purée (use a hand held mixer or food processor) until the mixture is thick, light and fluffy. Add the cream, return to a boil, then reduce the heat and keep warm over a very low fire.
NOTE: If you are making this gravy for a Turducken, you can use the drippings. As soon as the Turducken has come out of the oven and the drippings have been drained off, add the drippings to the gravy. If the gravy is too thick, add some stock to adjust. Just before serving, increase heat and return to a full boil. Remove from heat and serve.