Ingredient

Sinigang Broth

• 1 (33.8-ounce) package fish broth (such as Aneto)
• 2 medium-size plum tomatoes (about 8 ounces), quartered lengthwise
• 1 small (6-ounce) yellow onion, peeled and halved lengthwise
• 1 (1-inch) piece fresh ginger, peeled and thinly sliced
• 4 medium garlic cloves, smashed
• 1 small (11-ounce) red grapefruit
• 1 ½ tablespoons fish sauce, plus more to taste
• 1 teaspoon fresh lemon juice (from 1 lemon)
• Fine sea salt, to taste

Additional Ingredients

• 12 deveined unpeeled head-on raw large Argentinean prawns (about 1 1/2 pounds) or 1 1/2 pounds deveined unpeeled head-on raw extra-large shrimp
• 1 tablespoon seasoning salt (such as Johnny's Fine Foods)
• 1 tablespoon canola oil, divided
• 12 medium shishito peppers (about 3 ounces)
• Small fresh cilantro leaves and thinly sliced watermelon radish, for serving

Direction

1. Bring fish broth, tomatoes, onion, ginger, and garlic to a boil in a medium saucepan over medium. Reduce heat to medium-low; simmer, uncovered, until flavors meld and liquid has reduced to about 3 1/4 cups (about 6 3/4 cups including solids), about 45 minutes.
2. Using a Y-shaped peeler, remove grapefruit peel in 6 to 8 long strips. Cut grapefruit in half crosswise, and squeeze to yield 1/2 cup juice. Discard squeezed grapefruit. Remove broth mixture from heat, and add grapefruit juice and peel strips. Let mixture stand 10 minutes. Pour mixture through a fine wire-mesh strainer set over a medium-size heatproof bowl; discard solids. Return strained broth to saucepan; stir in fish sauce and lemon juice. Add salt and additional fish sauce to taste. Cover and keep warm over low.
3. Preheat grill to medium-high (400°F to 450°F). Toss together prawns, seasoning salt, and 2 teaspoons oil in a medium bowl. Toss together shishito peppers and remaining 1 teaspoon oil in a separate medium bowl. Arrange prawns and shishito peppers on unoiled grates; grill, uncovered, turning occasionally, until prawns are cooked through and peppers are lightly charred and tender, about 4 minutes per side. (Prawn shells will start to release from the meat when they're cooked through.)
4. Divide sinigang broth evenly among four bowls. Arrange 3 prawns and 3 shishito peppers in each bowl. Garnish with cilantro and radish, and serve.