Making the batter: Proof the yeast as per the directions in the packet. (Note: Rapid Rise Yeast can be mixed directly with the flour, I used active dry yeast hence I proofed it separately)
In a medium-sized bowl, add all-purpose flour, yeast mixture (if proofed separately), corn starch and mix well.
Add yogurt, oil, and water to this mixture and whisk them well till no lumps remain.
Fermenting the batter
Take a large bowl and fill it with warm water. Place the bowl with the batter inside this larger bowl. Cover the larger bowl with either a towel or a plate and set it aside for 30 minutes.
Make the sugar syrup
On a gas stove, place a deep medium-sized saucepan on medium heat, add sugar, water, and cardamom powder (if using) and bring this mixture to a boil.
Reduce heat to medium-low and continue to cook until one string consistency is achieved (please see tips above). Reduce heat to a simmer.
Preheat oil for frying
Heat oil in a deep dish pan on medium-high heat. (Note: This oil will be used for deep frying the Jalebis so make sure you are using enough oil to completely immerse the jalebis).
Making Jalebis
After 30 minutes, the batter should have fermented. Add the coloring if using. Whisk the batter well. The consistency of the batter should be thick but it should flow freely as well.
Pour the batter in a piping bag. Use a smaller spout for thin jalebis.
Squeeze the batter into the hot oil in circular motions.
Fry for a minute or so till they turn golden and then flip the jalebis and cook the other side.
Remove the jalebis using tongs making sure you shake off the excess oil and place them in the sugar syrup. Let them rest for a minute or so and then flip the jalebi and wait for another minute before transferring them into another plate.
Make sure you shake the jalebi off before removing to shake off the excess sugar syrup. Repeat the process with the remaining jalebis.
Serve them hot!
Notes
I have included the nutritional info for jalebi from Nutritionix as an example and I can't vouch for its accuracy since I am not a nutritionist or dietician. For a homecook it is difficult to calculate the nutritional info for deep fried foods.