Make lamb ragù. Preheat oven to 160°C/325°F. Trim excess fat from lamb, if necessary. Combine onion, garlic, tomatoes, paste, bay leaves, and wine in a large oven bag. Combine spices in a small bowl. Rub oil over lamb, then spice mixture; place lamb in oven bag. Place lamb in bag on a large oven tray. Seal the bag using the tie provided, then pierce five or six times near the top of the bag to allow steam to escape during cooking. Roast 4 hours or until lamb is very tender. Discard bay leaves.

Preheat oven to 240°C/475°F.

Cut eggplants lengthways into medium-thick slices. Spray each side with cooking-oil spray. Place on wire racks on oven trays. Roast 10 minutes or until soft and brown at edges. Remove from oven. Reduce oven to 200°C/400°F.

Meanwhile, melt butter in a medium saucepan over medium heat, add flour; stir until mixture bubbles. Gradually pour in milk, whisking continuously until mixture boils and thickens. Add ½ cup (40g) of the parmesan, stir until melted. Remove from heat.

Remove lamb from oven bag; shred meat. Place cooking sauce from oven bag in a large saucepan over low heat, add shredded meat; stir ragù until heated through. Season to taste.

Combine bread crumbs, rind, thyme and remaining parmesan in a medium bowl.

Grease a 24cm x 32cm x 6.5cm deep (9½-inch x 12¾-inch x 2¾-inch) (3.5-litre/14-cup capacity) ovenproof dish. Place half the eggplant slices in the dish, then top with half the ragù and half the white sauce. Repeat layering. Cover white sauce with breadcrumb mixture.

Bake moussaka for 35 minutes or until golden and heated through.