Using a food processor, grind chiles, ginger, mint and cilantro very fine.
In a bowl, combine flour, yogurt and 2 cups water. Mix well until very smooth.
Heat oil in a skillet. Add mustard seeds. After they start popping, add asoefetida. Wait 10 seconds for it to stop sizzling.
Add flour-yogurt mix, sugar, black salt and salt. Bring to a boil. Reduce to a simmer and cook 8-10 minutes, stirring occasionally. After the first 5 minutes, stir frequently to prevent sticking.
Add grinded chile-herb mixture and stir to combine. Cook another 1/2 minute.