Preheat the broiler. Slice the scallops in half horizontally. Spray two small or one large gratin dish lightly with cooking spray. Arrange the scallops in a single layer in the dishes, and season with salt.

Mix the lemon zest, cilantro, and panko together in a small bowl. Sprinkle over the scallops.

Mash together the butter, ras-el-hanout, and harissa in a small bowl. Place one dollop of compound butter on each scallop.

Sit the gratin dishes on a rimmed baking sheet, and broil until the panko is crisp and the scallops are opaque, 10 minutes. Serve right away.