1. Slice the courgettes on an exaggerated diagonal so they are about 12cm long. Peel the onion and cut into rounds, keeping the layers together. Lay the pepper on its side, cut off the stem and slice into rings, removing the seeds and pith.
2. Heat a ridged grill pan or frying pan, brush the vegetables with the olive oil and fry over a medium high heat until soft and coloured, about 10 minutes, turning over half way through cooking. You may need to do this in batches. This can be done in advance and kept in the fridge or at room temperature until ready to serve.
3. Meanwhile make the dressing. Place the lentils in a small saucepan and cover with water. Bring to the boil, cover and simmer for 15-20 minutes or until tender. Drain off excess water and return to the pan. Mix the vinegar, oil, garlic, salt, pepper and basil and add to the warm lentils. The dressing can also be made in advance. Leave at room temperature.
4. To assemble, lay a handful of rocket on each plate and arrange the grilled vegetables on top. Spoon over the lentil dressing, discarding the garlic clove. Garnish with freshly torn basil leaves.