Cut the aubergine into bite-sized chunks. Finely chop the onion and mince the garlic.
Heat 2 Tbsp oil in a heavy based pan over a low heat. Add the aubergine, onion, garlic and bay leaves, then gently sauté under cover for about 20-30 minutes.
Meanwhile, finely chop the tomato.
When the aubergine is soft but not mushy, add the remaining oil, the tomato, parsley and lemon juice. Cook for a further 8 minutes or so until both tomato and aubergine are soft. Stir in the mint and lemon zest. Season with salt and pepper.
Discard the bay leaves before serving.