Put the aubergine slices in a large bowl, pour over the oil and toss well, using both hands to coat as evenly as possible. The oil will be absorbed fast, so work as quickly as possible. Set aside for 10 minutes while making the pesto.
Mix all the pesto ingredients together in a jug. Season with a little salt and pepper.
Heat a griddle pan until smoking, then lay several of the aubergine slices on to the hot pan in a single layer and cook over a high heat for 1–2 minutes on each side until lightly charred and soft. Transfer to heatproof platter and keep warm in a low oven while cooking the remaining slices.
Drizzle or spoon some of the pesto over the aubergine slices and serve with warm pitta bread, with the remaining pesto separately.