Flank Steak with Shiitake Mushroom Sauce Recipe

Ingredients

• Steak:
• 1/2 teaspoon salt
• 1/4 teaspoon black pepper
• 1 (1-pound) flank steak, trimmed
• Cooking spray
• Sauce:
• 1/2 cup chopped onion
• 1 garlic clove, minced
• 2 cups thinly sliced shiitake mushroom caps (about 1/2 pound mushrooms)
• 1 cup less-sodium beef broth
• 1/3 cup dry white wine
• 1 tablespoon balsamic vinegar
• 1/2 cup minced green onions