For meat mixture, in a medium mixing bowl combine the cornmeal, milk, onion, garlic, salt, oregano, and lemon-pepper seasoning. Add ground lamb and beef and mix well. Shape mixture into eight 1/4-inch-thick patties (about 4-inch diameter).

For filling, in a small mixing bowl combine feta and milk. Place 1 tablespoon feta mixture in centers of 4 of the patties. Top with remaining patties; press edges to seal.

For seasoning, in a small bowl combine cumin and ground red pepper. Sprinkle seasoning mixture over patties.

To grill indirectly: In a covered grill arrange preheated coals around a drip pan. Test for medium heat above the pan. Place meat on the grill rack over the drip pan. Cover and grill for 18 to 22 minutes or until an instant -read thermometer inserted into the side of the burger registers 160 degress F, turning once halfway through grilling time.

To grill directly: Grill meat on the grill rack of an uncovered grill directly over medium coals for 12 to 16 minutes or until an instant read thermometer inserted into the side of the burger registers 160 degress F, turning once halfway through grilling time.

To serve, split pita bread rounds in half crosswise. Serve meat patties in pita halves with spinach. Makes 4 servings.