Filling:. Heat oil. Add fennel, mustard and ginger. When mustard crackles, add garam masala, chili powder and asafetida. Stir briefly. Add cauliflower and salt and stir. Cook for 10 minutes or so. Can add few tbsp of water or so if cauliflower is sticking. Add peas and cook for a further 10 minutes or so. Again a bit of water may be needed. Let the filling cool to room temperature. Then mix in crumbled feta.