1. Preheat oven to 300°.
2. Combine first 7 ingredients in a small bowl. Add seeds to sugar mixture, stirring to coat. Spread seed mixture evenly on a baking sheet lined with parchment paper and coated with cooking spray. Bake at 300° for 15 minutes. Stir mixture; bake an additional 15 minutes. Place parchment on a wire rack; cool pumpkinseed mixture. Break into small pieces; set aside.
3. Preheat oven to 350°.
4. Cut squash in half lengthwise; discard seeds and membrane. Brush oil over cut sides of squash; sprinkle cut sides with 1/4 teaspoon salt. Place squash, cut sides down, on a jelly-roll pan. Bake at 350° for 1 hour and 20 minutes or until squash is tender. Cool slightly. Scoop out squash pulp from skins; discard skins.
5. Place squash pulp and broth in a blender. Remove center piece of blender lid (to allow steam to escape); secure blender lid on blender. Place a clean towel over opening in blender lid (to avoid splatters). Blend until smooth. Pour pureed mixture into a medium saucepan; stir in 2 cups water and remaining 1/2 teaspoon salt. Cook over medium-high heat 5 minutes or until thoroughly heated. Top each serving with seeds.