Tapioca Pearls

4 quarts water

1 cup large tapioca pearls

Soup:

2 tablespoons canola or vegetable oil

3/4 cup chopped yellow onion

1/2 cup chopped tomato

1/3 cup peeled, chopped carrot

1/4 cup chopped leek, white part only

1/4 cup finely chopped lemongrass, bulb part only

2 tablespoons peeled and finely chopped fresh ginger

2 gererous tablespoons julienned kaffir lime leaves

1 teaspoon chopped garlic

1 tablespoon curry powder

3 cups chicken broth

2/3 cup unsweetened coconut milk

1 tablespoon rice vinegar

1 tablespoon sugar

Garnishes:

16 large shrimp (21/25 count), peeled and deveined

salt and freshly ground black pepper

2 teaspoons unsalted butter

16 bite-sized mango slices

16 sprigs cilantro