Barley and vegetable soup

Ingredients

• 100 g Pearl barley
• 1 Small knob of butter (about 1 tbsp)
• 1 tbsp Olive oil
• 1 tsp Chopped rosemary
• A pinch of chilli flakes
• 1 Onion finely chopped
• 1 Carrot cut into small squares
• 1 Leek finely chopped
• 1 Garlic clove crushed
• 1000 ml Chicken stock (Homemade if possible)
• Juice of 1 lemon
• 1 tbsp Tarragon vinegar (Optional)
• Salt and white pepper to season
• Shaved parmesan to serve