Step 1

Heat broth, vinegar, soy sauce and sriracha in a medium saucepot over medium-high heat.

Step 2

In small bowl, combine cornstarch and cold water and stir until smooth and blended.

Step 3

Stir cornstarch mixture into broth in saucepot.

Step 4

Add mushrooms, tofu and ½ cup scallions and bring to a boil. Boil 1 minute.

Step 5

Reduce heat and simmer 10 minutes or until soup has thickened slightly and mushrooms are tender.

Step 6

Spoon into soup bowls and top with remaining scallions.