Preparation time: About 20 minutes. Cooking time: About 7 minutes.

For traditional fajitas, strips of barbecued skirt steak are rolled in flour tortillas. This version is lower in fat; you stir-fry round steak and vegetables, then serve the mixture in crisp lettuce.

1 lb. lean top round steak
1 tbsp. salad oil
2 cloves garlic, minced or pressed
1 lg. onion, thinly sliced
2 fresh jalapeno chilies, seeded and minced
1 lg. red bell pepper, seeded and cut into thin strips
2 tsp. ground cumin
3 tbsp. lime juice
1 tsp. cornstarch
1/2 lb. pear-shaped (Roma-type) tomatoes, diced
1 lime, cut into 8 wedges
8 lg. iceberg lettuce, leaves, chilled
1 lg. onion, chopped
1 c. nonfat plain yogurt

Cut steak with the grain into 1-inch-wide strips; then cut each strip across the grain into 1/8-inch-thick slices. Set aside. Heat oil in a wok or 14 to 14- inch frying pan over high heat; add meat and stir-fry until browned (1 1/2 to 2 minutes). With a slotted spoon, transfer meat to a bowl.

Add garlic, sliced onion, chilies, and bell pepper to pan. Stir-fry until onion is soft (about 3 minutes). Stir together cumin, lime juice, and cornstarch; add to pan with meat and tomatoes. Stir until mixture comes to a boil, then transfer to warm serving dish and garnish with lime wedges.