Cut the aubergine in half lengthwise and steam over a pan of boiling water for about 20 minutes till soft
Allow to cool slightly, then chop into chunks and tear the mint into the aubergine, mixing well
Top and tail the courgettes, then using a potato peeler, slice the courgettes into ribbons
Cut the fish and tomato (if fresh) into chunks
In one pan soften the garlic and seal the tuna, then stir through the tomato and aubergine and allow to rest while you cook the courgettes
In a largish non-stick frying pan, heat a teaspoon of olive oil, then gently soften the courgettes over a moderate heat till they start to go translucent.
Stir through the sauce, season with salt, pepper and lemon juice to taste and tear in the basil leaves