1. Preheat oven to 350°F. Spray a 2½-qt. baking dish with cooking spray; set aside. In a bowl, toss Cheddar and Asiago cheeses with 1 Tbsp. flour; set aside.
2. Cut 1 cup of squash cubes in half. Cook pasta per package directions; add cut-up squash during last 4 minutes of cooking. Drain pasta and squash.
3. Meanwhile, place remaining squash in a microwave-safe bowl and sprinkle with water. Cover and microwave on HIGH 9 to 11 minutes or until very soft, stirring halfway through. Drain. Transfer to food processor and process until mashed.
4. In a large saucepan, melt 1 Tbsp. butter. Add shallot; cook over medium heat 1 to 2 minutes or until softened. Whisk together milk and remaining 1½ Tbsp. flour until combined; add to shallot in pan. Stir in rosemary, black pepper, and mashed squash. Cook and stir 2 to 3 minutes or until thickened. Stir in cheese mixture. Cook and stir 1 minute.
5. Stir cooked pasta and squash pieces into sauce mixture. Transfer to prepared baking dish. Mix remaining 1 Tbsp. butter with panko crumbs; sprinkle over pasta. Bake 25 to 30 minutes or until heated through and bubbly around edges.

Each serving contains: 306 calories, 9 g fat, 5 g saturated fat, 0 g trans fat, 25 mg cholesterol, 304 mg sodium, 43 g carbohydrates, 4 g fiber, 7 g sugar, 16 g protein. Daily values: 95% vitamin A, 11% vitamin C, 32% calcium, 14% iron.