Bring a large pan of water to the boil and get a bowl of iced water ready. Blanch the remaining basil leaves for 5 secs. Using a pair of tongs, lift out the leaves and plunge them into iced water so that they cool quickly and keep their colour.
Once cool, lift the leaves out and squeeze to remove any excess water.
Add the blanched basil leaves to a food blender and pour in 60ml of olive oil. to a pourable sauce, adding more oil if needed, then put in a bowl and set aside.
For the ratatouille, halve the pepper, then deseed and slice into thin strips. Cut the courgette into quarters lengthways and slice. Slice the aubergine into thick rounds, then cut each one into strips.
