Heat the oils in a Large heavy-based pan, add the shallots and sweat until softened. Add the lemongrass, garlic and ginger and continue to cook gently, stirring for 3–4 minutes. Add the vegetables and cook slowly for 10 minutes more, stirring from time to time, until the vegetables slightly caramelize.
Add the stock, bring to the boil and simmer for 20–25 minutes