Melt the butter in a frying pan and fry the onion and garlic for 2-3 minutes, or until softened. Add the sweet potato and stock and bring to a gentle simmer for 5-6 minutes, or until the sweet potato is tender.
Add the spinach and herbs and stir until wilted, then add the cream and blend until smooth with a stick blender.
To serve, ladle the soup into a serving bowl and top with the poached egg. Drizzle over the sesame oil and garnish with the chopped herbs.
