Heat oil in pan, add chopped onions and garlic and green chillies.
Add finely chopped spinach leaves.
Cut potatoes to medium sized cubes.
Add it. Sprinkle 1/4 cup of water and close the pan. Stir occasionally.
After 10-15 minutes, when the spinach and potatoes are cooked, add red chillie powder, turmeric powder, garam masala powder, tamarind powder and salt.
Add 1/4 more cup of water and stir in high flame. Remove from flame.
Add chopped coriander and butter for garnishing.
Serve hot. Goes excellent with Rotis/Paraths/Plain Rice.