Red Lentil and Harissa Soup

Ingredients

• 1 tbsp olive oil
• 1 large onion, finely chopped
• 2 garlic cloves, finely chopped
• 2 tbsp finely chopped coriander stems
• 1–2 tbsp harissa paste (depending on how much heat you want)
• 200g red lentils, rinsed 1 litre vegetable stock
• 400g can of tomatoes squeeze of lemon (optional)
• 1 1/2 litres vegetable stock or water
• sea salt
• black pepper
• Gremolata
• zest of 1 lemon
• 1 garlic clove, finely chopped
• coriander leaves, finely chopped