Toss the green plantains with the chile powder, turmeric, water and salt. Leave to sit for 15 minutes.
I a large skillet, heat 3 tablespoons oil.
Add mustard seed. After they start to pop, add asoefetida, curry leaves, red chile, urad dal and channa dal. Fry for 1 minute until the dal starts to change color.
Add plantains and stir fry for 5 minutes, until plantains are cooked through.
Add cabbage and cook another 3 minutes.
Add coconut and salt, to taste. Stir to combine and stir fry for another 1/2 minute.