Photograph: Martin Poole
Trim the courgette and slice it diagonally, then trim the aubergine and slice it into rounds. Halve, deseed and chop the pepper into chunky pieces. Halve the onion, then slice it into wedges through the root.
Preheat a griddle pan. Brush the veg with oil, then griddle, in batches, until tender and lightly charred; set aside.
Brush the chicken breasts with oil and season. Griddle over a medium-high heat for 10-12 minutes or until cooked through, turning now and again. Meanwhile, gently heat the tomatoes, sugar, chilli and a pinch of salt in a pan until the tomatoes soften. Remove from the heat and stir in the basil.
Slice the chicken and arrange on a platter along with the veg. Spoon over the tomatoes and drizzle with olive oil.
Get ahead: griddle the vegetables a few hours ahead.