Halve aubergines lengthways, scoop out centers, season with salt, and drain upside down on a wire rack.
Heat olive oil in a pan and fry chopped onion and garlic until tender.
Add beef and fry until browned, breaking up lumps, then stir in cinnamon, cumin, salt, and pepper.
Add chopped tomatoes and enough water to cover, then simmer for 30 minutes.
Stir in bulgur wheat, pine nuts, and currants.
Preheat the oven to 170°C.
Place aubergine halves in a lightly oiled dish and fill with the meat mixture.
Whisk tomato purée, lemon juice, sugar, olive oil, 150ml water, salt, and pepper in a bowl.
Pour sauce over aubergines, cover with foil, and bake for 45 minutes.
Remove foil, baste aubergines, and bake for another 15-20 minutes until tender.