Preheat the oven to 200°C (180°C fan)/gas mark 6.
Line a large roasting tray with baking paper.
Chop 1 red pepper and 1 courgette into bite-sized pieces, then thinly slice half a red onion.
Arrange the red pepper, courgette, broccoli florets, cherry tomatoes and sliced red onion on the lined tray. Drizzle with olive oil, sprinkle over the garlic, mixed dried herbs, salt and pepper, then toss everything to coat. Spread out in a single layer.
Roast for 20–25 minutes, until the vegetables are tender and lightly caramelised.
Meanwhile, bring a large saucepan of salted water to the boil and cook the wholewheat spaghetti until al dente, following the pack instructions. Before draining, reserve about 100ml of the cooking water.
Drain the spaghetti and transfer it to a large bowl.
Add the roasted vegetables to the pasta.
Squeeze the juice of 1 lemon over the pasta, then gently toss everything together. If the mixture is a little dry, add some of the reserved pasta water to loosen it.
Taste and adjust the seasoning if needed.
Serve immediately, topped with chopped fresh basil or parsley, if you like.