Cut butternut squash in half and scoop out the seeds. Place cut side down in a large baking dish and fill with 1/4-inch water. Bake 45-55 minutes, or until tender. Remove from oven and let cool slightly.
Reduce oven temperature to 375°F.
While the squash bakes, bring a pot of water to a boil with a pinch of salt. Add pasta and cook until just tender. Drain and set aside.
Measure 2 cups the butternut squash. Place in a food processor along shallots, sage, salt and pepper. Pulse until squash is smooth. Add in vegetable broth and pulse until well-combined.
In a small baking dish, place a third of the squash puree in the bottom. Add half the noodles, followed by the ricotta. Top ricotta with the next third of the sauce, then the remaining noodles. Finish with remaining sauce and shredded mozzarella.
Bake 25-30 minutes, or until cheese is browned.
This dish would work well with any type of squash puree, pumpkin or sweet potatoes. For more flavor, ricotta can be subbed out for blue cheese or gorgonzola.