Traditional spaghetti alla puttanesca

Ingredients

• Spaghetti
• 5 litre water
• 2 teaspoon salt
• 400 gram dried spaghetti
• Puttanesca sauce
• 2 tablespoon olive oil
• 2 anchovy fillets
• 1 onion, finely chopped
• 3 large cloves garlic, crushed
• 800 gram chopped tinned tomatoes
• 1 tablespoon capers, chopped
• pinch dried chilli flakes
• 1/3 cup mixed olives, sliced (or use whole if you prefer)
• 1/3 cup chopped flat-leaf parsley