Grab the garlic and thinly slice 5 of the cloves, set aside. Finely mince the remaining 3 cloves of garlic and add the minced cloves to a bowl. To the same bowl, add the olive oil, lemon juice, oregano, rosemary, creole seasoning, a tiny pinch of salt and a large pinch of pepper. Mix to combine.
Place the lamb in a roasting pan and cut small slits all over. Grab the slices of garlic and insert them into the slits on the lamb, then rub the olive/herb mixture all over. Pour in enough water (about 2 cups depending on the size of your roasting your pan) to just cover the bottom of the pan. Cover the pan with foil. Roast on lowest rack of oven for 40 minutes to 1 hour then remove the foil and lower the heat to 375 degrees F. Roast for another 40 to 50 minutes, or until the lamb reaches your desired doneness.
While the lamb is roasting, make the harissa spiced Tzatziki. In a medium size bowl or glass measuring cup combine the yogurt, lemon juice, olive oil, dill, oregano, garlic, harissa and pinch of salt and pepper. Stir in the cucumber. Store in the fridge until ready to serve.
When the lamb is done roasting, remove from oven and let rest about 30 minutes as the lamb continues to cook outside the oven.
Meanwhile, make the fries. Pour the canola into a 6-qt. Dutch oven, filling it about 3 inches up the sides. Heat over medium heat until a deep-fry thermometer reads 375 degrees F. Working in small batches, add the potatoes and fry, tossing occasionally, until tender and slightly crisp, about 4 minutes. Remove from the oil and drain on paper towels. Increase the temperature to high, and heat oil until thermometer reads 425 degrees F. Working in small batches, return potatoes to oil, and fry, tossing occasionally, until crisp and golden brown, about 2-4 minutes. Again transfer fries to paper towels to drain. Sprinkle the fries with seasoned salt.
Once the lamb has rested, shred or thinly slice the meat. Serve inside the warm pitas topped with fries, pickled red onions, radishes, cucumbers and feta cheese. Serve the harissa Tzatziki alongside the gyros. Enjoy!!
*To ensure the lamb is at room temperature, try and prep it about 1 hour before roasting.