Preheat the oven to 200°C (400°F), or 180°C if using a fan-assisted oven.
In a small bowl, combine the Parmesan cheese, garlic powder, oregano (or thyme), paprika, salt, and black pepper. Mix thoroughly to create a fragrant, evenly blended Parmesan mixture.
Lightly coat the bottom of a 22 x 33 cm (9 x 13 inch) glass baking dish with olive oil. Tilt the dish to ensure the oil spreads across the entire surface—this will help form a golden, crispy crust.
Sprinkle the Parmesan mixture evenly over the oiled surface. Avoid stirring or patting it down once scattered; the loose layer helps achieve that signature crunch.
Arrange the halved baby potatoes cut side down directly onto the Parmesan layer. Press each piece firmly so the surface makes full contact with the cheese. For extra crispness, drizzle or spray a small amount of olive oil over the top of the potatoes, then sprinkle lightly with salt.
Bake for 35 to 40 minutes, or until the potatoes are tender inside and the Parmesan base has turned deep golden brown and crisp. You can check the crust through the glass dish for color.
Once baked, allow the potatoes to rest for about 5 minutes to set the crust. Use a thin spatula to carefully separate sections of four potatoes at a time, cutting through the bonded Parmesan layer. Gently flip them over onto a serving platter so the crispy, golden cheese side faces up.
Serve warm, accompanied by the dipping sauce if desired. To make the sauce, mix sour cream and green onions until smooth and creamy. Garnish the potatoes with extra chopped green onions or chives before serving. Perfect as a side dish or a bite-sized party appetizer bursting with crunch and flavor.