In a heavy bottom pan, heat oil on medium high heat. Once the oil is hot, add the cumin seeds and let them sizzle for few seconds.
Add the cauliflower, turmeric, and crushed chili pepper and sauté it for 3- 4 minutes on medium heat.
Add the peas and potatoes along with the garam masala, amchur, and salt and mix well until all the vegetables are coated with the spices. Reduce the heat to low, cover the pot, and let the vegetables cook for 10 minutes. Add the lemon juice if not using amchur and mix well. Turn the heat off and add cilantro and mix.
Preheat the oven to 400 F. Follow the instructions on the puff pastry package to thaw the pastry dough. Meanwhile fill four 6-oz ramekins with the vegetable filling. Each ramekin should hold about 1 cup of filling. It may seem overstuffed but you want the right filling-to-pastry ratio for the pot pie.
Cut the pastry sheet into four squares and place them over the filled ramekins. Make a cross with a knife on the top of the pastry to let the steam out while the pies bake. Brush the pastry with the beaten egg.
Bake the pot pies for 20 to 25 minutes or until the pastry is golden brown and puffed up.
Serve warm. To reheat, place the pies in the oven at 300 F for about 10-15 minutes.