1. Bring a large pot of water to a boil. Salt the water and add the butternut squash. Cook until soft, about 12-15 minutes.
2. While the squash is cooking, fry the sage leaves. Heat 3 tablespoons olive oil in a small skillet over medium-high heat until surface is shimmering slightly. Add a few leaves at a time and cook until crisp, but still bright green, about 30 seconds. Transfer to a paper towel to drain. Season with salt. Set aside.
3. Using a large slotted spoon, carefully remove the squash from the water and place in a large bowl. Add the pasta to the boiling water and cook according to package instructions.
4. Place the cooked butternut squash in a large food processor or blender. Puree the squash until smooth. Add water or broth and puree until the sauce reaches your desired consistency. You may need a little more or a little less water depending on the size of your squash.