Sweet Potato Meringue Trifle with Candied Pecans

Preheat oven to 425 degrees F. Toss sweet potatoes with vegetable oil, maple syrup, and 1/2 teaspoon salt on a rimmed baking sheet. Roast until tender and caramelized, 20 to 25 minutes; let cool. Meanwhile, in a large nonstick skillet over medium heat, combine brown sugar, pecans, and a pinch of salt. Cook, stirring constantly, until pecans are toasted and sugar melts and coats the nuts. Transfer to a plate to let cool. Using an electric mixer on medium-high speed, beat egg whites and cream of tartar until foamy. Gradually add 1 cup sugar in a steady stream and continue beating until still peaks form, about 6 minutes, then beat in vanilla. In individual serving glasses, layer roasted potatoes, candied pecans, and meringue, ending with meringue and reserving some pecans for sprinkling. Broil or use a kitchen torch to brulée the meringue tops, then serve.