Preheat oven to 375ºF and line a large rimmed baking sheet with foil. Lightly mist foil with cooking spray. Slice off tops of squash and cut each into quarters. Using a spoon, scoop out and discard seeds and fibers.
Place 1/2 tsp. butter inside each squash quarter and drizzle each with 1/4 tsp. maple syrup. Sprinkle with salt and pepper. Place squash quarters on baking sheet, spaced far enough apart so they don't touch.
Bake until squash is tender, 35 to 45 minutes. Serve hot.