Preheat oven to 425°.
Cut the pumpkin into 4 wedges, discarding seeds and membrane. Place the pumpkin wedges, cut sides up, in an 11 x 7-inch baking dish coated with cooking spray. Place 1/2 teaspoon butter on each wedge, and sprinkle each wedge with 1 1/2 teaspoons sugar. Bake at 425° for 35 minutes or until tender.