Preheat your oven to 425°F (220°C) for perfectly crispy potatoes.
In a large mixing bowl, combine quartered baby potatoes and sliced sweet potato. Drizzle with 2-3 tablespoons of olive oil, then sprinkle paprika, oregano, garlic powder, salt, and pepper. Toss to coat evenly.
Spread the seasoned potatoes evenly on a baking sheet in a single layer. Roast in the preheated oven for 25-30 minutes, flipping halfway, until golden brown and crispy.
While potatoes roast, prepare the tahini yogurt sauce by combining Greek yogurt, tahini, lemon juice, 40ml olive oil, and 20-30ml water in a mixing bowl. Season with salt and pepper. Whisk until smooth, adjusting water to desired consistency.
Remove roasted potatoes from oven and let cool slightly. Serve topped with tahini yogurt sauce, garnished with fresh parsley, sesame seeds, and a drizzle of olive oil.