Preheat oven to 350°. Cover a heavy metal baking pan with parchment paper.
Cut the stems off of the squashes and put them into a medium bowl. Sprinkle in olive oil, garlic slices, salt and pepper and toss to coat.
Spread in a single layer on prepared baking sheet and bake for 15 minutes. Remove tray from oven and toss squashes gently. Return to oven and bake an additional 10 minutes, or until squashes are fork-tender.