Sauté the diced pumpkin in butter, then add the lemongrass and let it sweat briefly, add the chicken broth and cook for 20 to 30 minutes; now remove the lemongrass and puree the pumpkin with the magic wand; Add the finely chopped coriander and season the soup with cayenne pepper and salt.
If you like, you can add sambal oelek or Asian spicy sauces. Garnish with a dollop of whipped cream just before serving