Put all the vegetables and garlic on a large baking sheet and drizzle over the olive oil. Place in a preheated oven, 220°C (425°F), Gas Mark 7, for 20–25 minutes until tender and beginning to char.
Cook the quinoa, meanwhile, in a saucepan of boiling water according to the pack instructions, then drain well.
Whisk together the pesto or tomato paste and balsamic vinegar in a small bowl. Place the roasted vegetables, rocket and quinoa in a large serving bowl and stir in the dressing. Serve warm.