Melt the butter in a heavy pot over medium heat. Stir in the onion, carrots and jalapwno. Sauté, stirring often, for 10 minutes. Add the thyme, bay leaf and broth and bring to a boil. Reduce to simmer and cook, partially covered about 25 minutes or until the carrots are tender. Remove bay leaf. Purée in the blender and return to the pot. Whisk in the cream and season to taste with salt. Reheat, but do not boil Serve hot, topped with chopped cilantro. Serves 6 to 8.