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. Toss to coat.
Spread in a single layer on prepared baking sheet and bake for 15 minutes. Toss and bake an additional 10 minutes, or until squashes are fork-tender.