Step 1

Preheat oven to 400°F with oven racks in middle and top positions. Stir together 2 tablespoons olive oil, khalta hara, coriander, and ginger in a small bowl to form a paste. Rub spice mixture evenly over fish (about 2 teaspoons per fillet). Place lemon slices 4 inches apart on a baking sheet. Top each lemon slice with 1 parsley stem and 1 cilantro stem. Top with fish fillets, and set aside at room temperature 15 minutes. Stir together serrano chile, parsley leaves, and cilantro leaves in a small bowl. Stir together garlic, salt, lemon juice, and remaining 2 tablespoons oil in a separate bowl.

Step 2

Roast fish on middle rack of preheated oven until a meat thermometer inserted in thickest portion registers 140°F, 10 to 12 minutes. Toss lemon juice mixture with serrano mixture until evenly coated. Serve each fillet with 1/4 cup herb mixture, tahini salad, and flatbread.