Ingredients

• 1 cup boiling-hot water
• 1/3 cup bulgur
• 3/4 teaspoon salt
• 1 medium onion, quartered
• 1/4 cup packed fresh cilantro leaves
• 1/4 cup packed fresh flat-leaf parsley leaves
• 1 lb ground lamb
• 1/2 teaspoon paprika (not hot)
• 1/4 teaspoon ground allspice
• 1/4 teaspoon black pepper
• 1/4 teaspoon cayenne
• 1 small garlic clove
• 1/8 teaspoon salt
• 1/2 cup walnuts (1 1/2 oz)
• 1/4 cup water
• 1 teaspoon fresh lemon juice
• 1/8 teaspoon cayenne
• 4 (4-inch) pita loaves
• 1 tablespoon olive oil
• Paprika (not hot) for dusting
• Garnish: fresh cilantro sprigs

Instructions

1. Pour boiling-hot water over bulgur with 1/2 teaspoon salt in a small bowl and soak 15 minutes, then drain in a sieve.
2. Mince garlic and mash to a paste with salt (1/8 teaspoon) using a large heavy knife, then transfer to a food processor and blend with remaining sauce ingredients until smooth. Transfer to a bowl.
3. Preheat broiler.
4. Pulse onion and herbs in cleaned processor until finely chopped, then transfer to a bowl and stir in bulgur, lamb, paprika, allspice, pepper, cayenne, and remaining 1/4 teaspoon salt until just combined. Form lamb mixture into 4 patties (4 inches in diameter).
5. Arrange pitas on a baking sheet. Brush with oil, then lightly dust with paprika and season with pepper. Broil on lowest rack until toasted, 1 to 3 minutes (watch to prevent burning). Keep pitas warm, loosely covered with foil, while broiling burgers.
6. Oil rack of a broiler pan and heat 4 inches from heat until hot, 3 to 5 minutes.
7. Broil burgers, turning over once, until cooked through, 5 to 7 minutes total. Serve burgers on pitas, topped with sauce.