Preheat oven to 425 degrees F (220 degrees C). Prepare a baking sheet with cooking spray.
Spray squash pieces with cooking spray to coat; transfer to a bowl. Season squash with parsley, kosher salt, and black pepper; toss to coat and arrange onto prepared baking sheet.
Bake in preheated oven for 15 minutes, turn with spatula, and continue baking until soft in the center, about 15 minutes more.
