Spicy-Tangy Beef Soup

3/4 lb round steak tips, 1/8 to 1/4 inch thick
1 (14.5 oz) can vegetable broth
1 1/2 c sliced mushrooms
1 c julienned carrots
3 Tbsp kikkoman lite soy sauce, divided
2 Tbsp red wine vinegar
1/2 tsp crushed red pepper flakes
1 oz uncooked angel hair pasta, broken up
2 Tbsp corn starch, disolved in 1/4 c water
1/4 c sliced green onions

Cut steaks lengthwise in half and then crosswise in 1/4 inch strips. In 3-quart saucepan over medium-high heat combine broth, mushrooms, carrots, 2 Tsp soy sauce, vinegar and red pepper flakes. Bring to a boil; reduce heat and simmer, uncovered, 5 minutes. Add pasta and simmer 5 minutes more. Stir in cornstarch mixture. Bring to boil once again; cook and stir one minute. Stir beef into soup. Immediately remove from heat. Cover and let stand 5 minutes. Stir in remaining soy sauce and green onions. Serve immediately.