Indian-Inspired Shrimp with Coconut, Chiles, and Tomatoes

Ingredients

• 2 tablespoons butter
• 2 teaspoons mustard seeds
• 2 teaspoons cumin seeds
• 1 cup finely chopped red onion
• 4 green serrano or jalapeño chiles, seeded and finely chopped
• 2 tablespoons minced fresh ginger
• 1 tablespoon minced garlic
• One 14.5-ounce can diced tomatoes, with juices
• One 13.5-ounce can unsweetened coconut milk
• 1 1/2 pounds medium shrimp, peeled and deveined
• 2 teaspoons salt
• 2 tablespoons chopped fresh cilantro
• 2 tablespoons chopped fresh chives (optional)
• Steamed basmati rice, for serving