Saffron Risotto

Ingredients

• 1.5 litres of water
• 1 large onion
• ½ head of celery
• 2 carrots
• 90g Parmesan cheese, grated
• 2 tablespoons olive oil
• Unsalted butter (as needed)
• 400g risotto rice (Carnaroli)
• 2 wine glasses of dry white wine
• 2 pinches of saffron