Vegetable & pasta soup

Ingredients

• 1 tablespoon olive oil
• 1 large brown onion (200g), chopped finely
• 2 sticks celery (300g), trimmed, chopped coarsely
• 2 carrots (240g), chopped coarsely
• 3 cloves garlic, crushed
• 1 teaspoon dried oregano
• 1/4 teaspoon dried chilli flakes
• 1 litre (4 cups) boiling water
• 1 litre (4 cups) salt-reduced vegetable stock
• 125 grams tagliatelle
• 1/4 cup coarsely chopped fresh flat-leaf parsley
• 60 grams baby spinach leaves, torn