1. Preheat oven to 350 degrees. Put chocolate in a medium bowl. Heat cream with cinnamon in a small saucepan over medium heat until it just begins to simmer. Stir into chocolate to melt. Finely chop 2 tablespoons nuts; set aside. Stir remaining nuts into chocolate. Spoon chocolate into a resealable plastic bag; cut 1 inch off one corner.

2. Lay 1 sheet phyllo on a work surface (cover remaining sheets with a damp kitchen towel). Lightly brush surface with melted butter; lay another sheet on top, and brush with more melted butter.

3. Immediately pipe chocolate along a short side of phyllo, 11/2 inches from edges.Tightly roll into a log, lightly brushing with butter at each turn and tucking in ends. Brush log with butter; cover with a damp kitchen towel. Repeat process to make 2 more logs.

4. Transfer to a parchment-lined baking sheet; bake 15 minutes. Rotate sheet; brush logs with butter. Sprinkle with reserved nuts. Bake until golden, about 15 minutes more. Let cool completely; dust with sugar. Cutting in a swift motion, divide each log into 8 pieces.