1. Preheat the oven to 400°F and line a baking sheet with parchment paper.

2. Lightly flour your work surface and unfold the puff pastry sheet. Roll it gently to smooth the seams and shape it into an even rectangle.

3. In a small bowl, mix the brown sugar, granulated sugar, cinnamon, and salt.

4. Brush the puff pastry all over with the melted butter, then sprinkle the cinnamon sugar mixture evenly across the surface.

5. Fold the pastry in half lengthwise to cover the filling, then press lightly so the layers hold together.

6. Cut the folded dough into even strips using a sharp knife or pizza cutter.

7. Twist each strip several times and place the twists on the prepared baking sheet, leaving a little space between each one.

8. Whisk the egg with the water and brush the tops of the twists.

9. Bake for 14 to 17 minutes, or until puffed and golden brown.

10. Let the twists cool slightly on the pan.

11. If using glaze, whisk together the powdered sugar, milk, and vanilla extract until smooth, then drizzle over the twists before serving.