1 boneless beef sirloin steak, cut 1 1/4" thick (approx. 2 lb.)
1/4 c. packed brown sugar
4 tsp. cider vinegar
1 tbsp. vegetable oil
2 tsp. chili powder
1 tsp. salt
1/2-1 tsp. hot pepper sauce
1 carton (8 oz.) plain low-fat yogurt
1/3 c. minced green onions & tops
1/4 tsp. garlic salt
1 pkg. (10 oz.) fresh spinach (optional)
Red bell pepper slices (optional)
Paprika

Trim fat from boneless beef sirloin steak; cut steak into 1 1/2 inch pieces. Mix brown sugar, vinegar, oil, chili powder, salt and hot pepper sauce in medium bowl. Add beef pieces; toss to coat. Let stand 15 minutes.

Meanwhile, stir together yogurt, green onions and garlic salt; set aside. Wash spinach; discard stems and pat dry. Coarsely chop spinach; set aside.

Thread beef pieces on 6 to 8 (9 inch) metal skewers. Place beef on grid over medium coals. Grill beef 8-10 minutes, to desired doneness (rare or medium), turning frequently.

To serve, place spinach around edge of large serving platter leaving center open for small serving bowl. Remove beef from skewers and arrange over spinach. Garnish beef with peppers. Put yogurt sauce in serving bowl; sprinkle with paprika. Place bowl in center of platter. 6-8 servings.

Test about 4 inches above coals for medium with 4 second hand count.