Heat 1 tb ghee in a skillet. Saute the cumin seeds until golden. Add onion, cauliflower & peas & mix well. Mix in asafetida & mango powder, stir.
Add garam masala, salt & cayenne. Cover the pan & cook over a moderate heat for 10 minutes. Remove pan from heat & cool. Divide mixture into 8 equal portions.
Take one half-moon of pastry & brush the edges with water. Fold into a cone. Fill pastry with 1 portion of cauliflower mixture & seal the top. Repeat with the rest of the pastry.
Heat sufficient ghee (or vegetable oil) in a wok or large skillet to deep fry 4 samosas at a time. When very hot, deep-fry each samosa for a few minutes, until golden brown, flipping once to cook both sides. Drain on paper towels.
NOTE: To avoid excess fat I like to deep-fry the samosas, drain them very well & then reheat them in a toaster oven at 350F for 5 minutes or so. If you place them on a grill while re-heating them, extra oil can also drain off.