Heat the oil in a pot and add the onions. Saute until reddish brown.
Add the ginger-garlic paste, tomatoes, powdered spices and salt. Stir-fry this masala until thick and shiny. Add a few splashes of water if required.
Add the grated beets and a glass of water. Cook covered on medium heat until the beets have softened and the water has dried. (30 minutes)
Add the green chillies and cook uncovered for 2 minutes more.
Garnish with fresh cilantro leaves.
Notes
If you don't have powdered garam masala at hand, put some whole spices - 3 cloves, 3 green cardamom and ¼ teaspoon black peppercorns. The sabzi will taste just as nice.