Branzino with Herbs and Tomato Jam

INGREDIENTS

• 1/4 vegetable oil
• 3 yellow mustard seeds
• 1 ground coriander
• 1/2 ground cardamom
• 2 medium shallots, thinly sliced
• 2 garlic cloves, chopped
• 2 chopped peeled ginger
• 1/4 fish sauce (such as nam pla or nuoc nam)
• 1/4 sugar
• 1 ground turmeric
• 1 crushed red pepper flakes
• 4 beefsteak tomatoes (about 2 pounds), coarsely chopped
• 2 fresh lime juice
• Kosher salt, freshly ground pepper
• 4 1-pound whole branzino, cleaned
• 1 (packed) fresh tender herbs (such as basil, dill, cilantro, and/or flat-leaf parsley)