Ingredients

1 medium onion, cut into chunks2 garlic cloves2 tablespoon sugar1 tablespoon ground mustard1/2 teaspoon ground ginger1-1/2 teaspoons pepper1/2 teaspoon cayenne pepper1/2 cup reduced-sodium soy sauce1/4 cup water1 beef sirloin tip roast (2 to 3 pounds), cut into 1/4-inch-thick slicesCUCUMBER SAUCE:1 medium cucumber, peeled, seeded and cut into chunks4 garlic cloves1/2 teaspoon salt1/3 cup cider vinegar1/3 cup olive oil2 cups sour cream8 to 10 pita breads, warmed and halvedThinly sliced onionChopped tomato

Preparation

In a blender, combine the onion, garlic, sugar, mustard, ginger, pepper and cayenne; cover and process until onion is finely chopped. Add soy sauce and water; process until blended.

Place the beef in a shallow dish. Add marinade and turn to coat; cover and refrigerate for 1-2 hours.

For sauce, in a blender; combine the cucumber, garlic and salt; cover and process until cucumber is chopped. Add vinegar and oil; process until blended. Transfer to a large bowl; stir in sour cream. Refrigerate until serving.

Drain and discard marinade. Grill beef, covered, over medium-hot heat until meat reaches desired doneness (for medium-rare, a thermometer should read 135°; medium, 140°; medium-well, 145°). Place beef in pita halves. Top with cucumber sauce, sliced onion and chopped tomato. Refrigerate any remaining sauce.