To Make Jalebi: Combine all purpose flour, cornstarch, yogurt, food color (if using), hot oil and lemon juice to form a smooth batter.
Cover and set it aside for 12 to 24 hours to ferment. It should be foamy with bubbles and smell fermented. Mix the batter really well to make it more workable.
Make the Sugar Syrup: Combine sugar and water in a saucepan and bring to a boil. Simmer until it reaches single string consistency. (When you take a drop of the syrup between 2 fingers and stretch, it should stretch in 1 single thread).
Keep the syrup warm and ready.
Make Jalebis: Pour the batter into a ketchup bottle with a small hole or pour into a ziplock bag and make a tiny hole in the corner.
Heat oil for deep frying. Carefully pipe the batter in circles into the oil. Cook till the jalebis are crisp. Remove from the oil and place them in the syrup for 2 to 3 minutes, turning them around to coat evenly.
Remove and place them on a wire rack to cool. Enjoy them hot, warm or at room temperature. Store in an airtight container, they keep well for up to 2 to 3 days.
To make Poha: Wash poha 2 to 3 times, drain and set aside until ready to use. There should be just a little bit of water left in the poha but not a lot.
Heat 2 tsp oil in a pan, add mustard seeds and once they start to splutter, add fennel seeds, onions, green chilies and curry leaves. Cook until onions turn translucent, this takes about 3 to 4 minutes.
Add turmeric, potatoes and cook covered until potatoes are tender. Alternately potatoes can be microwaved until tender beforehand and can be added here to save time.
Add the poha and mix well. Cover and cook on low heat for 5 minutes.
Turn off the heat and sprinkle with chopped cilantro.
Serve immediately with the garnishes of your choice.