Melt butter in a skillet. Cook apples, cranberries, brown sugar and cinnamon over medium heat for 6–8 minutes, until softened and most released liquid evaporates. Cool about 20 minutes.

Heat oven to 400°F. Lightly flour the counter and roll pastry to about 10x12 inches. Spread cooled filling thinly, leaving a 1-inch border along one long edge.

Roll from the opposite long edge into a log. Seal the bare edge, then cut into 12 slices. Set cut-side up on a parchment-lined baking sheet and brush exposed pastry with beaten egg.

Bake 20–25 minutes until pastry is golden and cooked through. Cool 10 minutes. Dust lightly with powdered sugar through a food-safe star stencil, if desired.