Spicy Lentil Soup with Pumpkin, Tomato and Green Beans

Ingredients

• 1 tbsp olive oil
• 1 onion (chopped)
• 2 celery stalks (chopped)
• 2 carrots (chopped)
• 2 garlic cloves (crushed)
• 2 tbsp korma curry paste
• 1 kg butternut squash (chopped)
• 410 g diced tomatoes
• 3 cups vegetable stock
• 400 g brown lentils (rinsed and drained)
• 100 g green beans (cut into short lengths)
• 1/2 cup Greek-style yogurt (low-fat, to serve)