Ingredients

1 tablespoon canola oil 

1 medium onion, coarsely chopped (1 cup) 

1 garlic clove, crushed 

Shrimp shells from 1/2 pound small shrimp (from Rice Noodles with Chicken, Pork, and Shrimp) 

1 bay leaf 

1/4 teaspoon red-pepper flakes 

3 tablespoons fish sauce 

2 cups homemade or low-sodium store-bought chicken stock 

1 cup water 

Preparation

Heat oil in a saucepan over medium heat. Add onion and garlic, and cook until softened, about 4 minutes. Add shrimp shells, bay leaf, and red-pepper flakes, and cook, stirring, until shells are bright pink, about 1 minute. Add fish sauce, and cook for 1 minute. Stir in stock and water. Raise heat to medium-high, and bring to a boil. Reduce heat, and simmer, partially covered, 20 minutes. Pour through a fine sieve; discard solids. Stock can be stored in an airtight container in the refrigerator for up to 3 days or in the freezer for up to 1 month.