Roasted Butternut Squash and Rosemary Gratin

Ingredients (6)

• 3 cups (about 3 pounds uncooked) mashed butternut squash
• 1/4 cup freshly grated Parmesan cheese,
• 1/2 teaspoon kosher salt
• 1/2 to 3/4 teaspoon chopped fresh rosemary
• 1/4 teaspoon freshly ground black pepper
• 1/4 cup shredded Asiago cheese