In a small bowl, mix together ginger-garlic paste, tomato paste and all the dry spices with 1/4 cup water into a paste. Keep aside.
Heat oil in a pan and saute the onion till light brown. Now add the spice paste and fry till the oil separates. Add the mince and the chopped coriander stems.
Mix well and cook, covered till dry. Keep breaking the lumps with the spatula during the process of cooking. When done, set aside to cool. Add little of the coriander leaves and mix well.
Pour a layer of the idli batter in a greased steel container / tiffin box. Spread 2-3 tbsp. of the keema over it, followed by some coriander leaves and idli podi. The final layer should be of the idli batter.
Steam for 20-22 minutes (5-7 minutes on a high flame and the remaining on a medium to low flame.)
Set aside for 15-20 minutes before demoulding it. Serve these delicious Stuffed Keema Idlis with coconut chutney and sambar.