Thaw the frozen puff pastry sheets as per package instructions. Alongside, once you take out the pastry sheets from freezer for thawing, immediately start working on the filling.
For the filling, heat oil in a pan and add hing, jeera, saunf and dhaniya seeds to it. Once it all splutters, add split green chilies to it. Saute for a few seconds.
Add ginger garlic paste and saute again. Now, add the spices (salt, coriander powder, turmeric powder, garam masala, chaat masala and red chili powder) and mix.
Add a tablespoon of water and mix again. Add mashed potatoes and mix them evenly with the masalas.
Add the dried and crushed kasoori methi to the potatoes, along with schezwan chutney and lemon juice. And give it a final mix.
Finally, sprinkle some chopped coriander leaves, mix, and switch off the flame. Keep aside the filling for later use.
Preheat the oven to 400°F (200°C).
Take the thawed pasty sheet, unfold it carefully, spread some flour on your kitchen surface (where you want to prepare the puffs) and lightly dust both sides of the sheet. Cut it into 9 (3*3) equal squares as shown in the picture.
For making one puff, take one square and roll it from all sides using a rolling pin (For measurement idea, I rolled the square from ~3 inches to a 4-5 inch square for final use). Apply milk wash using a pastry brush to the 4 sides of each pastry square (on the side facing up). Add ~1 tbsp of filling on one side of each sheet.
Fold the pastry sheets into a rectangle. Then, using a fork, create a design on the folded sides.
Place all the rectangular pastry sheets on the baking tray lined with parchment paper. Finally, apply milk wash on top part of all the prepared pastry rectangles.
Bake them in the preheated oven for around 20-25 minutes.
Once done, remove the baking tray from the oven.
Serve the hot, crispy and flaky Aloo Puffs aka Aloo Patties with Tomato sauce or dip of your choice.