1 Rinse celery, pat dry and remove any strings. Peel carrots. Rinse bell pepper, wipe dry, cut into quarters and remove the seeds.
2 Peel zucchini. Rinse leek well and pat dry. Cut away the green part of the leek and reserve for another use.
3 Finely dice vegetables.
4 Heat oil in a pot. Cook vegetables over medium-low heat, stirring frequently, for 7-8 minutes.
5 Peel the garlic and finely chop. Add garlic to vegetables and cook for another 2 minutes.
6 Add tomatoes to pot and bring to a boil. Reduce heat to medium and cook for 30 minutes, stirring frequently.
7 Meanwhile, cook the pasta in a pot of boiling salted water until al dente according to package directions, then drain.
8 Season the vegetable sauce with salt, pepper and oregano and serve with the pasta.