1. Bring a large pot of water and a medium saucepan of lightly salted water to a boil.
2. In a blender, combine 1 cup of the vegetable stock with the blistered cherry tomatoes, 2 tablespoons of basil, the roasted garlic and the parsley. Blend until pureed. Transfer the mixture to a saucepan with the remaining 1 cup of vegetable stock, chili flake, and salt and pepper to taste. Bring to a boil over high heat, then reduce the heat to medium and simmer briskly until the liquid reduces and thicken slightly.
3. While the sauce reduces, in separate batches, boil each of the vegetables for 1 minute in the saucepan of salted water. As each vegetable is done, remove it with a wire skimmer, rinse under cold running water until cool, drain well, and transfer to a bowl.
4. Add all the vegetables to the sauce and stir well to heat them through. Keep warm.
5. As soon as the large pot of water comes to a boil, salt the water. Add the pasta and cook until al dente – tender but still slightly chewy – following the manufacturer’s suggested cooking time.
6. Drain the pasta and stir it, still slightly dripping, into the sauce until well coated. Remove the pan from the heat and stir in the parmesan, if using.
7. To serve, divide the pasta and vegetables among four large warmed plates or pasta bowls. Sprinkle each plate with some of the remaining 2 tablespoons of basil. Serve immediately.