In a jar or bowl, combine lemon juice, olive oil, garlic, sugar, dried herbs, salt, pepper, and chilli flakes. Shake or whisk until well blended. Set it aside so the flavours can develop while you prepare the vegetables.
Preheat your oven to high heat. Toss all vegetables except asparagus with olive oil, salt, pepper, and garlic. Spread them on baking trays in a single layer and roast until tender and slightly caramelised, then add asparagus in the last few minutes of roasting.
Transfer the hot roasted vegetables to a large bowl. Pour over half of the dressing while they are still warm. Let them marinate for at least 30 minutes so they absorb all the flavour.
Boil the pasta in well-salted water until slightly softer than al dente. Since pasta firms up when chilled, cooking it a little longer keeps it tender in the salad. Drain well but do not rinse.
Add the warm pasta to the marinated vegetables along with any roasting juices. Pour over the remaining dressing and sprinkle chopped parsley. Toss gently until evenly coated, then top with crumbled feta before serving.