Preheat the oven to 400°F / 205°C. Oil a 9 × 13in / 23 × 33cm baking dish.
Heat 1 tablespoon of olive oil in a skillet over medium heat. Cook 1 medium diced yellow onion until soft. Add 450g of ground chuck and cook, breaking it up, until browned.
Stir in ½ teaspoon of cinnamon, ¼ teaspoon of cayenne for the filling, 1 teaspoon of kosher salt, ¼ teaspoon of black pepper, and the juice of ½ lemon.
Rinse 1 cup of fine bulgur in a fine sieve and squeeze out the water. Combine with 450g of very lean, finely ground lamb or beef and 1 medium puréed sweet onion.
Add 1 tablespoon of table salt, ½ teaspoon of ground black pepper, 1 teaspoon of ground cinnamon, and ¼ teaspoon of cayenne. Knead to a smooth paste.
Press half the paste into the dish in an even layer. Spread the filling over it and cover with the remaining paste, smoothing the top.
Score the top into diamonds and dot with 2 tablespoons of butter, cut into small pieces, one on each diamond. Bake for about 50 minutes, until deep golden brown. Cool for 10 minutes before cutting.
