Preheat oven to 375°.
Cut squash in half lengthwise; remove seeds. Place squash halves, cut sides down, on a foil-lined baking sheet coated with cooking spray. Bake at 375° for 30 minutes or until tender. Scoop out pulp; set aside. Discard skins.
Heat 2 teaspoons oil in a large Dutch oven over medium heat. Add onion, parsley, sage, and thyme; cook 15 minutes or until lightly browned, stirring frequently. Add squash, water, 1 1/4 teaspoons salt, 1/4 teaspoon pepper, and minced garlic; bring to a boil. Partially cover, reduce heat, and simmer 25 minutes. Place about 2 1/2 cups squash mixture in a blender, and process until smooth. Pour pureed soup into a large bowl. Repeat procedure with remaining squash mixture, 2 1/2 cups at a time.
Heat 1 tablespoon oil in a large nonstick skillet over medium-high heat. Add radicchio, 1/4 teaspoon salt, and 1/4 teaspoon pepper; sauté 5 minutes or until lightly browned. Remove from heat; drizzle with vinegar, tossing to coat. Ladle 1 1/3 cups soup into each of 6 bowls. Top each serving with 1/3 cup radicchio and 1 tablespoon cheese. Yield: 6 servings.