Creamy Watercress Soup

Ingredients

• 1 tbsp olive oil
• 1 medium sized onion, finely chopped
• 2 cloves garlic, finely chopped
• 1 tsp curry powder
• 3 bunches of watercress, thoroughly washed, stalks intact
• 1½ pints vegetable stock
• Freshly ground black pepper
• Small carton of low fat crème fraîche