Thai pumpkin soup

Ingredients

• Sunflower oil – 4 teaspoons.
• Grated ginger – 1 tablespoon.
• Pumpkin or squash – 1-1/2 kg. (It should be peeled and roughly chopped).
• Sliced onion – 1 no.
• Bashed lemon grass -1 no.
• Coconut milk – 400 ml can.
• Thai red curry paste – 3 to 4 tablespoons.
• Lime juice – for seasoning.
• Sugar – for seasoning.
• Vegetable stock 850 ml.
• Sliced red chili – 1 no. (It should be sliced; optional item).