How to Make It
Heat oven to 450° F. On 2 rimmed baking sheets, toss the squash and mushrooms with the sage, oil, ½ teaspoon salt, and ¼ teaspoon pepper. Roast, tossing once and rotating pans halfway through, until the vegetables are tender, 20 to 25 minutes.
Meanwhile, cook the tortellini according to the package directions. Reserve ½ cup of the cooking water; drain the tortellini and return to the pot. Add the vegetables, fontina, ¼ cup of the cooking water, and ½ teaspoon salt and toss gently to coat (add more cooking water if the pasta seems dry). Sprinkle with additional fontina.