5.5 lb sweet potatoes, scrubbed
1 T. minced chipotle chiles in adobo, mashed to a paste
3 T. unsalted butter, cut into T. pieces and softened
1 tsp. salt

Put oven rack in middle position and preheat oven to 450°F. Line a baking sheet with foil and butter a 2-quart shallow glass or ceramic baking dish. Prick each potato several times with a fork, then bake on baking sheet until very soft, 1 to 1 1/2 hours. Reduce oven temperature to 350°F.When cool enough to handle, halve potatoes and scoop flesh into a bowl. Beat potatoes, chile paste (to taste), butter, and salt with an electric mixer at medium speed just until smooth, then spread in baking dish. Bake whipped potatoes until hot, 20 to 25 minutes. Cooks’ note: Whipped potatoes can be prepared and spread in baking dish (but not baked) 1 day ahead and chilled, covered. Bring to room temperature before baking.