Place an oven rack in the center position of the oven. Preheat the oven to 425°F. Line a baking sheet with parchment paper (OR foil lightly misted with nonstick cooking spray).
Wash and dry the yellow squash, and then cut each one into ¼-inch thick slices.
Arrange the squash rounds on the prepared pan, with little to no space between them.
Lightly sprinkle the squash with garlic salt and freshly ground black pepper.
Use a small spoon to spread a thin layer of Parmesan cheese on each slice of squash.
Bake for 15 to 20 minutes, or until the Parmesan melts and turns a light golden brown.
Serve immediately.
