Toss squash cubes with the scallion, 3 tablespoons grapeseed oil, and Himalayan pink salt, then roast until squash is soft, about 30 minutes. Set aside to cool.
Transfer cooked squash to blender with spring water and chopped sage. Blend until smooth. If to thick add 1-2 tablespoons of spring water. Keep warm.
In a skillet, warm 2 teaspoons of grapeseed oil over medium-high heat. Add the whole sage leaves and fry until the leaves are crispy. about 1 minute. Drain on paper towels.
In the same skillet over medium-high heat, toast the walnuts until golden then set aside on paper towels.
Add the butternut squash noodles to the skillet, pour in sauce to coat generously for 5-6 minutes until noodles are slightly softened (DO NOT OVER COOK)