Wash all the vegetables and cut into julienne strips. Place the 30g of butter into an anti-stick saucepan; sautée the carrots and peppers for 1 minute. Add a few tablespoons of water, salt and pepper to taste, and cook over moderate heat f or about 15 minutes; halfway though cooking, add the courgettes and asparagus.Cook the Candele in a pot full of salted water for 7- 8 minutes. Drain the pasta and mix with half the vegetable mixture, a tablespoon of béchamel sauce, and half the grated parmesan cheese.Pour the pasta and the remaining vegetable mixture into a buttered oven dish; cover the pasta with the remaining béchamel sauce and parmesan cheese. Bake au gratin at 190C for 10 minutes.