1. Preheat your oven to 400°F or 200°C and line a baking sheet with parchment paper.

2. Mix together the melted butter, granulated sugar, and ground cinnamon in a small bowl until they're well combined.

3. Roll out the puff pastry on a lightly floured surface to about 1/8 inch or 3 mm thick.

4. Evenly spread the sugar and butter mixture over the pastry, leaving a 1-inch or 2.5 cm border around the edges.

5. Add a layer of coarsely grated almonds over the sugar mixture.

6. Starting from the long side, tightly roll the pastry into a log and cut it into 16 equal pieces.

7. Position the rolls on the prepared baking sheet with about 1 inch or 2.5 cm of space between each bun.

8. Use the beaten egg to brush a golden glaze over the tops of the rolls.

9. Bake the rolls in the oven for 18-20 minutes or until golden brown.

10. Once done, take them out of the oven and let them cool for 5 minutes before serving.