Step 1: In a large mixing bowl, combine the ground lamb, ground beef, finely minced onion, minced garlic, dried oregano, dried marjoram, ground cumin, smoked paprika, salt, and black pepper. Use your hands to thoroughly mix the ingredients until just combined. Be careful not to overmix, as this can make the meat tough.
Step 2: Once mixed, press the meat mixture into a tightly packed log or loaf shape on a piece of plastic wrap. Wrap it securely and refrigerate for at least 1 hour, or preferably overnight. This chilling process is crucial as it allows the flavors to meld and the meat to firm up, making it easier to slice later.
Step 3: While the meat chills, prepare your homemade tzatziki sauce. In a medium bowl, combine Greek yogurt, grated and thoroughly squeezed cucumber, minced garlic, fresh dill, olive oil, white wine vinegar, and a pinch of salt and pepper. Stir well and refrigerate until ready to serve. This allows the flavors to deepen.
Step 4: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper. Take the chilled meat loaf and unwrap it. Carefully slice the meat into thin, even slices, about 1/8 to 1/4 inch thick. The thinner the slices, the crispier the edges will be, mimicking traditional gyro meat.
Step 5: Arrange the sliced meat in a single layer on the parchment-lined baking sheet. Place another sheet of parchment paper directly over the meat, then top with a second baking sheet (or a heavy oven-safe pan) to press the meat down. This pressing technique is key to achieving that flattened, slightly crispy texture characteristic of Parchment Paper Gyros.
Step 6: Bake for 20-25 minutes, or until the meat is cooked through and lightly browned. The internal temperature should reach 160°F (71°C). Remove the top baking sheet and parchment paper and, if desired, briefly broil for 2-3 minutes to get extra crispy edges, watching carefully to prevent burning.
Step 7: While the meat is cooking, warm your pita bread. You can do this in a dry skillet over medium heat for 30 seconds per side, in the microwave for 15-20 seconds, or wrapped in foil in the oven for a few minutes. Prepare your fresh toppings: slice tomatoes, red onion, and chop lettuce.
Step 8: To assemble your Parchment Paper Gyros, lay out a warm pita bread. Spoon a generous amount of the cooked gyro meat onto the pita. Top with sliced tomatoes, red onion, and lettuce. Finish with a dollop (or two!) of the fresh tzatziki sauce. Fold or roll your gyro and enjoy immediately.