Thaw the puff pastry sheets (if using frozen) but make sure they are still cold
Line 2 baking sheets with parchment paper, no need to grease them as the puff pastry contains enough fat
Unfold one sheet of the puff pastry sheets onto a lightly floured kitchen counter. Using a rolling pin, gently roll the top of the pastry to seal together any folds.
Spread ¾ of the sugar on top then fold the sheet the following way: Fold the top half into the middle as well as the bottom half into the middle but leave approx 1 inch / 2cm gap in the middle. Then repeat, for the top half into the middle and the bottom half into the middle again, again making sugar to leave some space in the middle.
Sprinkle the log with the remaining sugar, then using a sharp knife, cut the into 1 cm / ½ inch pieces and place them onto the baking sheet leaving enough space in between them to puff up.
If at any point the puff pastry would become warm to handle, pop it into the freezer for a few minutes to chill. Do not force the pastry while it is still hot, it would only make a mess.
Whisk one egg with a dash of milk then apply a light egg wash on top of the pastry, and dust with more sugar, if desired.
Pre-heat oven to 200C / 392F (no fan) while chilling the pastry either in the fridge or freezer. Chilling will keep the pastries´ shape better. Also, keep the second tray of pastries refrigerated while baking the first tray.
Bake them at 200C / 392F (no fan) for about 15 minutes on one side and further 10 minutes on the other side or until the top is golden brown and the bottom is evenly baked. Then, continue with the next tray using the leftover pastries.
Let them slightly cool in the baking tray for 5 minutes then move them onto a cooling rack.
Serve them fresh. Any leftovers can be stored at room temperature for 2-3 days.