How to Make It
Preheat the oven to 375°. Butter a 3-quart baking dish. In a large saucepan, cover the sweet potatoes with water and boil over high heat until tender, about 35 minutes. Let the sweet potatoes cool, then peel and slice them thickly.
Meanwhile, in a small saucepan, combine the cream with the cloves, star anise and nutmeg and simmer over low heat for 20 minutes. Remove from the heat and let stand for 10 minutes. Strain the cream, discarding the whole spices.
In a food processor, puree the sweet potatoes, in batches if necessary, with the spiced cream, butter and egg yolks. Scrape the soufflé base into a large bowl and season with 11/2 teaspoons of salt and 1/4 teaspoon of pepper.
In a clean stainless-steel bowl, beat the egg whites with a pinch of salt until firm peaks form. With a rubber spatula, fold one-third of the beaten whites into the soufflé base; fold in the remaining whites. Pour the soufflé mixture into the prepared dish and bake for about 1 hour, or until risen and firm. Let the soufflé rest for about 10 minutes.
Combine all of the ingredients in a medium saucepan and bring to a boil. Simmer over low heat, stirring occasionally, until very thick, about 20 minutes. Serve the molasses sauce warm alongside the sweet potato soufflé.