• 5 kg tomatoes
• 2-3 onions
• Olive oil
• 2-3 stalks of celery
• 1-2 zuchinni
• 2-3 capsicum
• 1 chilli
• 1 tbsp each of celery and mustard seeds
• Fresh herbs such as basil, thyme and oregano
• Salt and pepper

Chop up the tomatoes and cook them slowly in their own juices in a large pot until tender. Pass them through a mouli or course sieve and set aside. Gently saute the vegetables in a pan with a splash of oil until softened and then combine with the tomatoes and herbs. Boil together until thickened, season to taste and then freeze the concentrate in 1 cup packs ready for use.