Heat enough oil in a pan, fry the crushed fennel seeds, add the chopped onions, chopped green chillies and ginger garlic paste, saute until the raw smell goes away, add the thawed green peas, salt, red chilli powder, garam masala powder and saute until the vegetables gets slightly cooked.
Add the cooked mashed potatoes, grated paneer, cook everything on simmer until the masala turns thick.
Preheat the oven to 350F.
Roll the puff pastry sheet dusted with flour as a rectangle, using a cookie cutter cut them as 8 circles.
Place enough masala in a circle and close it with an another circle, press the edges with a fork, arrange them over a baking sheet lined over a baking tray, finish the remaining puff pastry circles as the same way and bake for 20-25 minutes in the middle rack until the crust turns golden brown.