Heat a large heavy based frying pan and add little olive oil. Add onion, zucchini and carrot and sauté on low-medium heat for 5 minutes, stirring frequently. Add garlic and continue to sauté for 1 minute. Add tomatoes and let simmer for 15 minutes, stirring occasionally. Empty contents of frying pan into a food processor and whiz mixture for 1-2 minutes so mixture is still thick but smooth. Serve warm with pasta, sweetcorn and pea fritters, baked meatballs or anything you like
Store in the fridge for up to 2 days or portion out and freeze sauce for up to 1 month.