How to Make It
Make pecans: Preheat oven to 300°F. Brush a large baking sheet with butter. Whisk egg white with salt until foamy, 2 to 3 minutes. Whisk in sugar and cinnamon (mixture will be thick). Stir in pecans. Spread on baking sheet. Bake, stirring often, until pecans are lightly browned and crisp, about 30 minutes. Let cool on a wire rack. (Can be made up to a week in advance. Keep in an airtight container.)
Raise oven temperature to 425°F. Roll out pie dough on a lightly floured surface into an 11-inch round. Fit into a 9-inch pie plate. Trim and crimp edges. Line with parchment and fill with pie weights. Bake until firm, about 10 minutes. Reduce oven temperature to 375°F; remove parchment and weights. Bake until crust is lightly browned around edges, about 7 minutes longer.
Make filling: Reduce oven temperature to 350°F. Peel sweet potatoes; cut into 1-inch chunks. Place in a pot, add salt and cover with cold water. Bring to a boil over high heat. Reduce heat to medium; cook until potatoes are very soft, 15 to 20 minutes. Drain; transfer to a large bowl. Using an electric mixer on medium speed, beat potatoes until smooth. Mix in butter, sugar, cinnamon, nutmeg and cloves. Scrape down sides of bowl. Beat in cream and eggs. Spoon into crust, then smooth top. Bake until a knife inserted into center comes out clean, 60 to 70 minutes.
While pie is still warm, arrange pecans over top (you might have extra nuts; reserve for another use). Cool completely before serving.