To make ravioli:
In a large frying pan on a med-low heat, sauté the onions in olive oil until they turn translucent. Add the mashed sweet potatoes, cumin, curry, allspice, garlic, salt and pepper to the onions. Mix well and allow to sauté for an additional 3-5 minutes. Set aside potato mixture and let cool to room temperature.
Bring 4 cups of water to a boil in a small soup pot; add desired amount of salt. While you wait for the water to boil, sprinkle counter with a little corn starch and lay out the ravioli rounds. Gently dab the perimeter of the ravioli with some warm water (this acts like a glue) and drop a spoonful of the sweet potato mixture in the center of the dough. Fold closed and pinch the ends of the ravioli to secure. Drop ravioli into the boiling water and cook until they float to the top, about 4-5 minutes. Scoop out with slotted spoon and keep warm on a plate.
To make creamy sauce:
Melt margarine in a saucepan over medium heat. Add flour and stir until mixture is well blended. Gradually stir in beef broth and non-dairy whipped topping. Cook over medium heat, stirring constantly, until sauce begins to boil and thickens. If using optional wine, add now. Simmer, stirring frequently, over very low heat for 5 minutes. Season with salt and pepper to taste.
Drizzle creamy sauce over sweet potato ravioli and garnish with fresh parsley.