Preheat oven to 400°. Place squash in a foil-lined 15x10x1-in. baking pan. Drizzle with oil; sprinkle with sage, salt and pepper. Toss to coat. Roast 30-35 minutes or until tender, stirring occasionally., Meanwhile, in a large saucepan, heat oil and 1 tablespoon butter over medium heat. Add onion and garlic; cook and stir 3-4 minutes or until softened. Reduce heat to medium-low; cook 30-40 minutes or until deep golden brown, stirring occasionally. Stir in salt, pepper flakes and pepper., Add water, sweet potato and carrot to saucepan. Bring to a boil. Reduce heat; cook, uncovered, 10-15 minutes or until vegetables are tender. Add squash mixture and remaining butter to soup. Puree soup using an immersion blender. Or cool soup slightly and puree in batches in a blender; return to pan and heat through.