1. In a small skillet, over medium-low heat, toast walnuts for 4 to 6 minutes, stirring often. Set aside.
2. In a large saucepan add squash pieces and water. Bring to a boil. Cover. Reduce heat to simmer and cook 10 to 12 minutes or until pieces are soft. Remove from heat.
3. In a blender, add soy milk, flour, garlic powder, onion powder, dried mustard, sage, brown sugar, salt-free seasoning, salt, and cooked squash pieces (with liquid). Blend 20 to 30 seconds or until smooth.
4. Pour mixture back into saucepan and stir with a wire whisk over medium-high heat for 2 to 3 minutes to thicken.
5. Serve sauce over fettuccine and top with toasted walnuts and parsley.
Makes 4 servings.