| 2 | Sprays cooking spray |
| 20 oz | Butternut squash, fresh, peeled and cubed |
| 1/8 tsp | Table salt, for cooking pasta |
| 12 oz | Uncooked whole-wheat pasta, penne |
| 1 1/4 cup | Fat-free skim milk |
| 2 tbsp | White all-purpose flour |
| 2 tsp | Minced garlic |
| 1/2 tsp | Table salt |
| 1/4 tsp | Black pepper, freshly ground, or to taste |
| 1 tbsp | Thyme, fresh, chopped, divided |
| 1/2 cup | Part-skim ricotta cheese |
| 1/3 cup | Grated Parmesan cheese, Parmigiano-Reggiano recommended |
| 1/4 cup | Chopped walnuts, toasted |
Preheat oven to 375ºF. Coat a baking sheet with cooking spray. Coat a 2 1/2- to 3-quart baking dish with cooking spray.
Place squash on prepared baking sheet; roast until tender, about 20 to 30 minutes. Place in a large bowl and mash.
Meanwhile, bring a large pot of salted water to a boil. After squash has been roasting for about 10 minutes, cook pasta according to package directions; drain and return to pot.
In a medium saucepan, whisk together milk, flour, garlic, salt and pepper. Bring to a boil over medium-high heat, whisking frequently; reduce heat to low and simmer, stirring often, until thickened, about 2 minutes. Remove from heat; stir in mashed squash and 2 1/2 teaspoons of thyme. Add sauce to pasta; toss to mix and coat.
Transfer pasta mixture to prepared baking dish; dot with spoonfuls of ricotta and then sprinkle with Parmesan and walnuts. Bake until top is lightly browned in a few spots, about 15 to 20 minutes; remove from oven and sprinkle with remaining 1/2 teaspoon of thyme. Yields about 1 cup per serving.