Preheat the oven to 400°F. Lightly grease a baking sheet with cooking spray. Spread the tater tots across the greased pan. Bake for 20 minutes.
Remove the tots from the oven. Increase the temperature to 450°F. Spray the bottom of a heavy measuring cup with oil and gently press down on each tot to flatten them. Return them to the oven and bake an additional 10-15 minutes, until they start to crisp.
Remove from the oven, flip each tot over, and top with Parmesan cheese, if desired. Bake an additional 5 minutes. Sprinkle with parsley and serve with the dipping sauce of your choice.