Arrange squash in a single layer on a jelly roll pan coated with cooking spray. Drizzle with 1 1/2 teaspoons oil; toss well to coat.
Bake at 450° for 25 minutes or until lightly browned. Set aside.
Cut the broccoli rabe crosswise into thirds. Cook broccoli rabe in boiling water 5 minutes; drain. Set aside.
Heat 1 1/2 teaspoons oil in a large saucepan over medium heat. Add onion and garlic; cook 5 minutes, stirring frequently.
Add squash, stock, and beans; cook 10 minutes. Place 1 1/2 cups vegetable mixture in a blender or food processor; process until smooth. Return puréed mixture to pan; stir in broccoli rabe and salt. Cook 5 minutes or until thoroughly heated.