1 1/2 pounds sweet potatoes, cleaned, pricked with a fork and left a bit damp
3/4 cup plus 1 to 2 tablespoons heavy cream
1/3 vanilla bean, split lengthwise and seeds scraped (may substitute 1 teaspoon vanilla extract or to taste)
1 teaspoon grated orange zest (optional)
2 tablespoons unsalted butter, at room temperature
Freshly ground white pepper
Preheat the oven to 350 degrees.
Place the sweet potatoes on a rimmed baking sheet and bake about 1 hour and 10 minutes or until the thickest part is fork-tender.
When cool enough to handle (10 to 15 minutes), peel and discard the skins. Transfer the potatoes to a medium bowl.
Meanwhile, in a large saucepan over medium heat, add 3/4 cup of the cream, the vanilla bean and seeds, and orange zest, if desired. Cook for 5 minutes. Discard the vanilla bean pod and remove from the heat.
Pour the cream mixture over the sweet potatoes. If preparing in advance, add 1 tablespoon of the butter and, using a whisk, stir until smooth. Add salt and pepper to taste. Set aside. When completely cooled, transfer to a shallow, covered container and refrigerate.
When ready to serve, melt the remaining tablespoon of butter in a medium pan over low heat. Add the sweet potato mixture and stir gently, until warmed throughout. If the puree seems dry, stir in 1 to 2 tablespoons of cream.
If not making in advance, add both tablespoons of butter to the potato and cream mixture and stir until smooth. Serve warm.
MAKE AHEAD: The entire dish can be made up to a day in advance and refrigerated in a sealed container. Reheat it on the stovetop