Thaw frozen puff pastry according to package directions. Preheat oven to 375°. Line 12 standard-size (2½-inch) muffin cups with paper liners; set aside.

Whisk together sugar, cocoa powder, and cinnamon in a small bowl. Sprinkle 1½ tablespoons sugar mixture on a work surface. Unfold 1 sheet of puff pastry on top of sugar mixture. Sprinkle 1½ tablespoons sugar mixture evenly over top. Sprinkle with 2 tablespoons chocolate chips and 2 tablespoons hazelnuts. Roll gently with rolling pin to a 12×9-inch rectangle, pressing the chocolate chips and nuts into pastry.

Roll up into a spiral, starting from a short side. Cut into 6 (1½-inch) slices. Place into prepared muffin cups with cut sides up. Repeat with remaining pastry sheet, sugar mixture, chocolate chips, and hazelnuts. Place in remaining prepared muffin cups.

Bake 22 to 25 minutes or until crisp and golden. Cool in pan on wire rack 10 minutes. Remove from pan to wire rack. If desired, remove paper liners. Pipe or spoon 1 teaspoon chocolate hazelnut spread on top of each cruffin. Garnish each with strawberry half, if desired. Serve warm.