This tangy side dish pairs well with pork chops, burgers, and Grilled Chicken Paillards with Mint Salad.
Heat broiler. Brush a rimmed baking sheet with 1 tablespoon oil. Arrange zucchini in a single layer, cut side up. Brush with 1 tablespoon oil and season with salt and pepper. Broil until zucchini are deep golden brown, 8 to 10 minutes.
Meanwhile, in a small bowl, stir together yogurt, lemon juice, coriander, and mustard. Season with salt and pepper. Transfer zucchini to a serving platter, drizzle with yogurt sauce, and sprinkle with cilantro.