In a mixing bowl, combine idli batter with ragi flour, salt and enough water to make a thick pourable batter. Cover and set aside for 20~30 minutes.
Cook the veggies:
Heat oil in a medium size pan on medium heat. Add mustard & cumin seeds and cook till they start to pop. Stir in ginger, green chilies and curry leaves; cook for 1 minute.Next add the veggies and cook on medium flame for 4~6 minutes or until the veggies are crisp tender. Season with salt. Turn off the heat and cool the veggie mixture for a few minutes. Add the veggies to the batter and mix until well combined.
Heat the ponganalu/ appe pan on medium heat.Add about ½~1 teaspoon of into each hole and pour 1~2 tablespoons of batter into each. Cover and cook 2~3 minutes or until lightly browned. Carefully flip each paniyaram and cook for 1~2 minutes until cooked through and golden.Serve hot with any chutney of choice.
If using refrigerated idli, then take it out about an hour before making the paniyaram.
Feel free to use your favorite veggies. Some of my favorites are onions, cabbage, carrot, green beans etc. Make sure to finely chop the veggies before adding to the batter.
I sometimes use store bought coleslaw mix. It is very convenient and easy.
You can totally skip the veggies or add whatever you have on hand. I sneak in a few veggies because they hide well and my kids haven't noticed them as of yet.
Ponganalu are best served hot. But if you have a few leftover, then refrigerate them in an airtight container for up to 2 days. Make sure to warm them in the microwave until heated through before serving.