Preheat the Oven. Preheat your oven to 400°F. Line a rimmed baking sheet with one sheet of parchment paper.

Mix the Meat. In a large bowl, combine the ground lamb or mutton, grated onion, minced garlic, olive oil, salt, paprika, cumin, oregano, and black pepper. Mix thoroughly until the mixture is well combined and slightly sticky—this helps the log hold its shape.

Roll Out the Meat. Transfer the meat mixture onto a clean sheet of parchment paper and press it into a rough rectangle. Place a second sheet of parchment on top. Use a rolling pin to roll the meat into a thin, even rectangle, approximately ¼ inch thick.

Form the Log. Carefully peel off the top sheet of parchment. Using the bottom sheet to guide you, roll the meat tightly into a compact log shape. Transfer the log, seam-side down, onto the prepared baking sheet.

Bake the Kebab. Bake for 20 minutes, until the meat is cooked through. Remove from the oven and carefully pour off and reserve the juices that have collected on the baking sheet—don't discard them.

Slice and Drizzle. Use a sharp knife or your hands to tear or slice the meat into doner-style pieces, mimicking the thin shavings of a traditional kebab. Spread the pieces out in a single layer on the baking sheet. Drizzle the reserved juices evenly over the meat.

Broil Until Crispy. Place the baking sheet under the broiler and broil for 5–8 minutes, turning the pieces once or twice, until the edges are slightly crispy and golden but not dry. Watch closely—broilers vary and the meat can go from perfect to overdone quickly. Remove and serve immediately.