Prepare instant polenta according to package directions, using a whisk.
Add in herbs, if using, and grated Parmesan cheese.
Coat a 7x11-inch baking sheet or pyrex/ceramic dish with cooking spray. Pour the polenta mixture into the pan quickly, and spread evenly with a spatula. Place pan in refrigerator to cool and set for 30 minutes. Meanwhile, preheat oven to 400°F.
Cut the polenta into squares or triangles.
Drizzle both sides of polenta pieces with olive oil and sprinkle with garlic powder/salt. Bake for about 45-50 minutes, or until crispy, turning half-way through to make sure they get crispy on both sides. Cool on a rack when done.
Best if used the same day, but you can store them in an airtight container in the refrigerator and reheat them until crisp the next day.