Method
1. Heat vegetable oil in a clean large saucepan
2. Add onion
3. Cook until softened - 5 min
4. Stir in garlic clove, ginger and Thai red curry paste
5. Cook - 1 min
6. Add coconut milk, vegetable stock, granulated sugar, fish sauce and lemongrass stalk
7. Boil
8. Add sweet potato
9. Simmer until tender - 10 min
10. Add tomatoes
11. Cook - 2 min
12. Divide content of large saucepan between 4 large serving bowls
13. Drizzle with lime juice
14. Garnish with cilantro and bean sprouts
15. Serve with warm rice or naan bread