Preheat your oven to 400°F. Prepare a large baking sheet (18x13 inches) by spraying it with non-stick cooking spray.
After scrubbing and rinsing the potatoes, cut each one in half, then slice each half into thick wedges. Aim for about 8 wedges per potato. Arrange them on the prepared baking sheet.
Drizzle the wedges with olive oil and sprinkle them with parmesan, garlic powder, rosemary, salt, and pepper (use about 1 tsp salt and 1/4 tsp pepper). Toss them gently to coat, then spread the wedges into a single layer, making sure they lie on one of their flat sides.
Roast in the oven for 30-35 minutes, flipping the wedges to their other flat side halfway through the cooking time. For extra crispiness, broil them during the final 1-2 minutes.
Once done, sprinkle a bit more parmesan on top, and garnish with fresh parsley if you’d like. Serve the wedges warm.
For the dipping sauce: In a small bowl, whisk together Greek yogurt, mayonnaise, basil, milk, garlic powder, and a pinch of salt. Add more milk if necessary to achieve your preferred consistency. Serve alongside the potato wedges.