Leek and Potato Soup

WHAT YOU'LL NEED

• 1 onion chopped
• 1 medium potato peeled and finely diced
• 1/4 celery stick
• 3 leeks trimmed, well washed and sliced
• 25 g Flora Buttery
• 1 Knorr Chicken Stock Cube or Knorr Vegetable Stock Cube dissolved in 800 millilitres boiling water
• 100 ml Elmlea Single
• 2 tbsp fresh chives, chopped