How to Make It
Prepare the Pecan Feuilletage: Preheat oven to 400°F. Stir together pecans and sugar in a small bowl. Place 1 layer of phyllo on a parchment paper-lined baking sheet; brush with some of the melted butter. Sprinkle with about 1 1/2 tablespoons pecan mixture. Cover with another layer of phyllo. Repeat process with remaining phyllo sheets, butter, and pecan mixture, ending with a butter-brushed phyllo sheet on top.
Bake in preheated oven until layers are golden brown, bonded together, and crispy, 12 to 14 minutes. Cool completely on baking sheet, about 30 minutes. Break apart, or cut into pieces.
Prepare the Mulled Wine: Stir together red wine, sugar, cinnamon, allspice, nutmeg, and cloves in a large saucepan over medium-high; bring to a boil, stirring occasionally. Reduce heat to medium, and cook, stirring occasionally, until mixture is syrupy and reduced to about 1 1/2 cups, 40 to 50 minutes. Remove from heat, and cool completely, about 30 minutes. Discard cloves.
Prepare the Mascarpone-Cane Syrup Mousse: Beat together mascarpone cheese, heavy cream, and cane syrup in a large bowl with the whisk attachment of an electric mixer on medium-high speed until stiff peaks form, about 1 1/2 minutes.
To assemble trifles: Divide fresh blackberries evenly among 8 (1/2-cup) serving glasses. Pour 3 tablespoons of Mulled Wine over berries in each glass. Top with 2 to 3 tablespoons Mascarpone-Cane Syrup Mousse and pieces of Pecan Feuilletage.