Preheat the oven to 180°C.
To make the chermoula combine the crushed garlic, cumin, coriander, chilli flakes, paprika and preserved lemon peel in a small bowl and then stir in about 2/3 of the olive oil.
Cut the eggplants in half length-ways and then score the flesh of each half with a diagonal crisscross pattern, making sure you don't cut all the way through.
Place your eggplant halves face up on a baking tray and spread the chermoula mix over each, getting it into the cuts you made. Place the tray into the preheated oven and bake for about 40 minutes until the eggplants are completely tender.