Preheat oven to 375F 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.